Merge pull request #391 from henkmollema/code-cleanup2

Code cleanup - take 2

Dapper/CommandDefinition.cs

@@ -18,9 +18,10 @@
 #endif
 
 namespace Dapper
-{    /// <summary>
-     /// Represents the key aspects of a sql operation
-     /// </summary>
+{
+    /// <summary>
+    /// Represents the key aspects of a sql operation
+    /// </summary>
     public struct CommandDefinition
     {
         internal static CommandDefinition ForCallback(object parameters)
@@ -34,125 +35,119 @@ internal static CommandDefinition ForCallback(object parameters)
                 return default(CommandDefinition);
             }
         }
-        private readonly string commandText;
-        private readonly object parameters;
-        private readonly IDbTransaction transaction;
-        private readonly int? commandTimeout;
-        private readonly CommandType? commandType;
-        private readonly CommandFlags flags;
-
 
         internal void OnCompleted()
         {
-            if (parameters is SqlMapper.IParameterCallbacks)
-            {
-                ((SqlMapper.IParameterCallbacks)parameters).OnCompleted();
-            }
+            (Parameters as SqlMapper.IParameterCallbacks)?.OnCompleted();
         }
+
         /// <summary>
         /// The command (sql or a stored-procedure name) to execute
         /// </summary>
-        public string CommandText { get { return commandText; } }
+        public string CommandText { get; }
+
         /// <summary>
         /// The parameters associated with the command
         /// </summary>
-        public object Parameters { get { return parameters; } }
+        public object Parameters { get; }
+
         /// <summary>
         /// The active transaction for the command
         /// </summary>
-        public IDbTransaction Transaction { get { return transaction; } }
+        public IDbTransaction Transaction { get; }
+
         /// <summary>
         /// The effective timeout for the command
         /// </summary>
-        public int? CommandTimeout { get { return commandTimeout; } }
+        public int? CommandTimeout { get; }
+
         /// <summary>
         /// The type of command that the command-text represents
         /// </summary>
-        public CommandType? CommandType { get { return commandType; } }
+        public CommandType? CommandType { get; }
 
         /// <summary>
         /// Should data be buffered before returning?
         /// </summary>
-        public bool Buffered { get { return (flags & CommandFlags.Buffered) != 0; } }
+        public bool Buffered => (Flags & CommandFlags.Buffered) != 0;
 
         /// <summary>
         /// Should the plan for this query be cached?
         /// </summary>
-        internal bool AddToCache { get { return (flags & CommandFlags.NoCache) == 0; } }
+        internal bool AddToCache => (Flags & CommandFlags.NoCache) == 0;
 
         /// <summary>
         /// Additional state flags against this command
         /// </summary>
-        public CommandFlags Flags { get { return flags; } }
+        public CommandFlags Flags { get; }
 
         /// <summary>
         /// Can async queries be pipelined?
         /// </summary>
-        public bool Pipelined { get { return (flags & CommandFlags.Pipelined) != 0; } }
+        public bool Pipelined => (Flags & CommandFlags.Pipelined) != 0;
 
         /// <summary>
         /// Initialize the command definition
         /// </summary>
         public CommandDefinition(string commandText, object parameters = null, IDbTransaction transaction = null, int? commandTimeout = null,
-            CommandType? commandType = null, CommandFlags flags = CommandFlags.Buffered
+                                 CommandType? commandType = null, CommandFlags flags = CommandFlags.Buffered
 #if ASYNC
-            , CancellationToken cancellationToken = default(CancellationToken)
+                                 , CancellationToken cancellationToken = default(CancellationToken)
 #endif
             )
         {
-            this.commandText = commandText;
-            this.parameters = parameters;
-            this.transaction = transaction;
-            this.commandTimeout = commandTimeout;
-            this.commandType = commandType;
-            this.flags = flags;
+            CommandText = commandText;
+            Parameters = parameters;
+            Transaction = transaction;
+            CommandTimeout = commandTimeout;
+            CommandType = commandType;
+            Flags = flags;
 #if ASYNC
-            this.cancellationToken = cancellationToken;
+            CancellationToken = cancellationToken;
 #endif
         }
 
         private CommandDefinition(object parameters) : this()
         {
-            this.parameters = parameters;
+            Parameters = parameters;
         }
 
 #if ASYNC
-        private readonly CancellationToken cancellationToken;
+
         /// <summary>
         /// For asynchronous operations, the cancellation-token
         /// </summary>
-        public CancellationToken CancellationToken { get { return cancellationToken; } }
+        public CancellationToken CancellationToken { get; }
 #endif
 
         internal IDbCommand SetupCommand(IDbConnection cnn, Action<IDbCommand, object> paramReader)
         {
             var cmd = cnn.CreateCommand();
             var init = GetInit(cmd.GetType());
-            if (init != null) init(cmd);
-            if (transaction != null)
-                cmd.Transaction = transaction;
-            cmd.CommandText = commandText;
-            if (commandTimeout.HasValue)
+            init?.Invoke(cmd);
+            if (Transaction != null)
+                cmd.Transaction = Transaction;
+            cmd.CommandText = CommandText;
+            if (CommandTimeout.HasValue)
             {
-                cmd.CommandTimeout = commandTimeout.Value;
+                cmd.CommandTimeout = CommandTimeout.Value;
             }
             else if (SqlMapper.Settings.CommandTimeout.HasValue)
             {
                 cmd.CommandTimeout = SqlMapper.Settings.CommandTimeout.Value;
             }
-            if (commandType.HasValue)
-                cmd.CommandType = commandType.Value;
-            if (paramReader != null)
-            {
-                paramReader(cmd, parameters);
-            }
+            if (CommandType.HasValue)
+                cmd.CommandType = CommandType.Value;
+            paramReader?.Invoke(cmd, Parameters);
             return cmd;
         }
 
-        static SqlMapper.Link<Type, Action<IDbCommand>> commandInitCache;
-        static Action<IDbCommand> GetInit(Type commandType)
+        private static SqlMapper.Link<Type, Action<IDbCommand>> commandInitCache;
+
+        private static Action<IDbCommand> GetInit(Type commandType)
         {
-            if (commandType == null) return null; // GIGO
+            if (commandType == null)
+                return null; // GIGO
             Action<IDbCommand> action;
             if (SqlMapper.Link<Type, Action<IDbCommand>>.TryGet(commandInitCache, commandType, out action))
             {
@@ -186,11 +181,12 @@ static Action<IDbCommand> GetInit(Type commandType)
                 il.Emit(OpCodes.Ret);
                 action = (Action<IDbCommand>)method.CreateDelegate(typeof(Action<IDbCommand>));
             }
-            // cache it            
+            // cache it
             SqlMapper.Link<Type, Action<IDbCommand>>.TryAdd(ref commandInitCache, commandType, ref action);
             return action;
         }
-        static MethodInfo GetBasicPropertySetter(Type declaringType, string name, Type expectedType)
+
+        private static MethodInfo GetBasicPropertySetter(Type declaringType, string name, Type expectedType)
         {
             var prop = declaringType.GetProperty(name, BindingFlags.Public | BindingFlags.Instance);
             ParameterInfo[] indexers;

Dapper/CustomPropertyTypeMap.cs

@@ -20,10 +20,10 @@ public sealed class CustomPropertyTypeMap : SqlMapper.ITypeMap
         public CustomPropertyTypeMap(Type type, Func<Type, string, PropertyInfo> propertySelector)
         {
             if (type == null)
-                throw new ArgumentNullException("type");
+                throw new ArgumentNullException(nameof(type));
 
             if (propertySelector == null)
-                throw new ArgumentNullException("propertySelector");
+                throw new ArgumentNullException(nameof(propertySelector));
 
             _type = type;
             _propertySelector = propertySelector;

Dapper/DataTableHandler.cs

@@ -3,7 +3,7 @@
 #if !DNXCORE50
 namespace Dapper
 {
-    sealed class DataTableHandler : Dapper.SqlMapper.ITypeHandler
+    sealed class DataTableHandler : SqlMapper.ITypeHandler
     {
         public object Parse(Type destinationType, object value)
         {

Dapper/DbString.cs

@@ -19,7 +19,7 @@ namespace Dapper
     /// <summary>
     /// This class represents a SQL string, it can be used if you need to denote your parameter is a Char vs VarChar vs nVarChar vs nChar
     /// </summary>
-    public sealed class DbString : Dapper.SqlMapper.ICustomQueryParameter
+    public sealed class DbString : SqlMapper.ICustomQueryParameter
     {
         /// <summary>
         /// Default value for IsAnsi.

Dapper/DefaultTypeMap.cs

@@ -11,7 +11,6 @@ namespace Dapper
     sealed class DefaultTypeMap : SqlMapper.ITypeMap
     {
         private readonly List<FieldInfo> _fields;
-        private readonly List<PropertyInfo> _properties;
         private readonly Type _type;
 
         /// <summary>
@@ -21,10 +20,10 @@ sealed class DefaultTypeMap : SqlMapper.ITypeMap
         public DefaultTypeMap(Type type)
         {
             if (type == null)
-                throw new ArgumentNullException("type");
+                throw new ArgumentNullException(nameof(type));
 
             _fields = GetSettableFields(type);
-            _properties = GetSettableProps(type);
+            Properties = GetSettableProps(type);
             _type = type;
         }
 #if DNXCORE50
@@ -184,12 +183,6 @@ public SqlMapper.IMemberMap GetMember(string columnName)
         /// </summary>
         public static bool MatchNamesWithUnderscores { get; set; }
 
-        public List<PropertyInfo> Properties
-        {
-            get
-            {
-                return _properties;
-            }
-        }
+        public List<PropertyInfo> Properties { get; }
     }
 }

Dapper/DynamicParameters.cs

@@ -198,7 +198,7 @@ protected void AddParameters(IDbCommand command, SqlMapper.Identity identity)
                     appender(command, template);
                 }
 
-                // The parameters were added to the command, but not the 
+                // The parameters were added to the command, but not the
                 // DynamicParameters until now.
                 foreach (IDbDataParameter param in command.Parameters)
                 {
@@ -246,7 +246,7 @@ protected void AddParameters(IDbCommand command, SqlMapper.Identity identity)
                 {
                     ((SqlMapper.ICustomQueryParameter)val).AddParameter(command, name);
                 }
-                else if (dbType == DynamicParameters.EnumerableMultiParameter)
+                else if (dbType == EnumerableMultiParameter)
                 {
 #pragma warning disable 612, 618
                     SqlMapper.PackListParameters(command, name, val);
@@ -276,12 +276,9 @@ protected void AddParameters(IDbCommand command, SqlMapper.Identity identity)
                             p.DbType = dbType.Value;
                         }
                         var s = val as string;
-                        if (s != null)
+                        if (s?.Length <= DbString.DefaultLength)
                         {
-                            if (s.Length <= DbString.DefaultLength)
-                            {
-                                p.Size = DbString.DefaultLength;
-                            }
+                            p.Size = DbString.DefaultLength;
                         }
                         if (param.Size != null) p.Size = param.Size.Value;
                         if (param.Precision != null) p.Precision = param.Precision.Value;
@@ -344,7 +341,7 @@ public T Get<T>(string name)
 
         /// <summary>
         /// Allows you to automatically populate a target property/field from output parameters. It actually
-        /// creates an InputOutput parameter, so you can still pass data in. 
+        /// creates an InputOutput parameter, so you can still pass data in.
         /// </summary>
         /// <typeparam name="T"></typeparam>
         /// <param name="target">The object whose property/field you wish to populate.</param>
@@ -383,13 +380,13 @@ public DynamicParameters Output<T>(T target, Expression<Func<T, object>> express
 
             do
             {
-                // Insert the names in the right order so expression 
+                // Insert the names in the right order so expression
                 // "Post.Author.Name" becomes parameter "PostAuthorName"
-                names.Insert(0, diving.Member.Name);
+                names.Insert(0, diving?.Member.Name);
                 chain.Insert(0, diving);
 
-                var constant = diving.Expression as ParameterExpression;
-                diving = diving.Expression as MemberExpression;
+                var constant = diving?.Expression as ParameterExpression;
+                diving = diving?.Expression as MemberExpression;
 
                 if (constant != null &&
                     constant.Type == typeof(T))
@@ -423,7 +420,7 @@ public DynamicParameters Output<T>(T target, Expression<Func<T, object>> express
             if (setter != null) goto MAKECALLBACK;
 
             // Come on let's build a method, let's build it, let's build it now!
-            var dm = new DynamicMethod(string.Format("ExpressionParam{0}", Guid.NewGuid()), null, new[] { typeof(object), this.GetType() }, true);
+            var dm = new DynamicMethod($"ExpressionParam{Guid.NewGuid()}", null, new[] { typeof(object), GetType() }, true);
             var il = dm.GetILGenerator();
 
             il.Emit(OpCodes.Ldarg_0); // [object]
@@ -446,7 +443,7 @@ public DynamicParameters Output<T>(T target, Expression<Func<T, object>> express
                 }
             }
 
-            var paramGetter = this.GetType().GetMethod("Get", new Type[] { typeof(string) }).MakeGenericMethod(lastMemberAccess.Type);
+            var paramGetter = GetType().GetMethod("Get", new Type[] { typeof(string) }).MakeGenericMethod(lastMemberAccess.Type);
 
             il.Emit(OpCodes.Ldarg_1); // [target] [DynamicParameters]
             il.Emit(OpCodes.Ldstr, dynamicParamName); // [target] [DynamicParameters] [ParamName]
@@ -478,10 +475,10 @@ public DynamicParameters Output<T>(T target, Expression<Func<T, object>> express
             {
                 // Finally, prep the parameter and attach the callback to it
                 ParamInfo parameter;
-                var targetMemberType = lastMemberAccess.Type;
+                var targetMemberType = lastMemberAccess?.Type;
                 int sizeToSet = (!size.HasValue && targetMemberType == typeof(string)) ? DbString.DefaultLength : size ?? 0;
 
-                if (this.parameters.TryGetValue(dynamicParamName, out parameter))
+                if (parameters.TryGetValue(dynamicParamName, out parameter))
                 {
                     parameter.ParameterDirection = parameter.AttachedParam.Direction = ParameterDirection.InputOutput;
 
@@ -493,14 +490,14 @@ public DynamicParameters Output<T>(T target, Expression<Func<T, object>> express
                 else
                 {
                     SqlMapper.ITypeHandler handler;
-                    dbType = (!dbType.HasValue) ? SqlMapper.LookupDbType(targetMemberType, targetMemberType.Name, true, out handler) : dbType;
+                    dbType = (!dbType.HasValue) ? SqlMapper.LookupDbType(targetMemberType, targetMemberType?.Name, true, out handler) : dbType;
 
                     // CameFromTemplate property would not apply here because this new param
                     // Still needs to be added to the command
-                    this.Add(dynamicParamName, expression.Compile().Invoke(target), null, ParameterDirection.InputOutput, sizeToSet);
+                    Add(dynamicParamName, expression.Compile().Invoke(target), null, ParameterDirection.InputOutput, sizeToSet);
                 }
 
-                parameter = this.parameters[dynamicParamName];
+                parameter = parameters[dynamicParamName];
                 parameter.OutputCallback = setter;
                 parameter.OutputTarget = target;
             });
@@ -518,7 +515,7 @@ void SqlMapper.IParameterCallbacks.OnCompleted()
         {
             foreach (var param in (from p in parameters select p.Value))
             {
-                if (param.OutputCallback != null) param.OutputCallback(param.OutputTarget, this);
+                param.OutputCallback?.Invoke(param.OutputTarget, this);
             }
         }
     }

Dapper/FeatureSupport.cs

@@ -28,7 +28,7 @@ private static readonly FeatureSupport
         /// </summary>
         public static FeatureSupport Get(IDbConnection connection)
         {
-            string name = connection == null ? null : connection.GetType().Name;
+            string name = connection?.GetType().Name;
             if (string.Equals(name, "npgsqlconnection", StringComparison.OrdinalIgnoreCase)) return postgres;
             return @default;
         }
@@ -39,7 +39,7 @@ private FeatureSupport(bool arrays)
         /// <summary>
         /// True if the db supports array columns e.g. Postgresql
         /// </summary>
-        public bool Arrays { get; private set; }
+        public bool Arrays { get; }
     }
 
 }

Dapper/SimpleMemberMap.cs

@@ -8,11 +8,6 @@ namespace Dapper
     /// </summary>
     sealed class SimpleMemberMap : SqlMapper.IMemberMap
     {
-        private readonly string _columnName;
-        private readonly PropertyInfo _property;
-        private readonly FieldInfo _field;
-        private readonly ParameterInfo _parameter;
-
         /// <summary>
         /// Creates instance for simple property mapping
         /// </summary>
@@ -21,13 +16,13 @@ sealed class SimpleMemberMap : SqlMapper.IMemberMap
         public SimpleMemberMap(string columnName, PropertyInfo property)
         {
             if (columnName == null)
-                throw new ArgumentNullException("columnName");
+                throw new ArgumentNullException(nameof(columnName));
 
             if (property == null)
-                throw new ArgumentNullException("property");
+                throw new ArgumentNullException(nameof(property));
 
-            _columnName = columnName;
-            _property = property;
+            ColumnName = columnName;
+            Property = property;
         }
 
         /// <summary>
@@ -38,13 +33,13 @@ public SimpleMemberMap(string columnName, PropertyInfo property)
         public SimpleMemberMap(string columnName, FieldInfo field)
         {
             if (columnName == null)
-                throw new ArgumentNullException("columnName");
+                throw new ArgumentNullException(nameof(columnName));
 
             if (field == null)
-                throw new ArgumentNullException("field");
+                throw new ArgumentNullException(nameof(field));
 
-            _columnName = columnName;
-            _field = field;
+            ColumnName = columnName;
+            Field = field;
         }
 
         /// <summary>
@@ -55,66 +50,39 @@ public SimpleMemberMap(string columnName, FieldInfo field)
         public SimpleMemberMap(string columnName, ParameterInfo parameter)
         {
             if (columnName == null)
-                throw new ArgumentNullException("columnName");
+                throw new ArgumentNullException(nameof(columnName));
 
             if (parameter == null)
-                throw new ArgumentNullException("parameter");
+                throw new ArgumentNullException(nameof(parameter));
 
-            _columnName = columnName;
-            _parameter = parameter;
+            ColumnName = columnName;
+            Parameter = parameter;
         }
 
         /// <summary>
         /// DataReader column name
         /// </summary>
-        public string ColumnName
-        {
-            get { return _columnName; }
-        }
+        public string ColumnName { get; }
 
         /// <summary>
         /// Target member type
         /// </summary>
-        public Type MemberType
-        {
-            get
-            {
-                if (_field != null)
-                    return _field.FieldType;
-
-                if (_property != null)
-                    return _property.PropertyType;
-
-                if (_parameter != null)
-                    return _parameter.ParameterType;
-
-                return null;
-            }
-        }
+        public Type MemberType => Field?.FieldType ?? Property?.PropertyType ?? Parameter?.ParameterType;
 
         /// <summary>
         /// Target property
         /// </summary>
-        public PropertyInfo Property
-        {
-            get { return _property; }
-        }
+        public PropertyInfo Property { get; }
 
         /// <summary>
         /// Target field
         /// </summary>
-        public FieldInfo Field
-        {
-            get { return _field; }
-        }
+        public FieldInfo Field { get; }
 
         /// <summary>
         /// Target constructor parameter
         /// </summary>
-        public ParameterInfo Parameter
-        {
-            get { return _parameter; }
-        }
+        public ParameterInfo Parameter { get; }
     }
 
 }

Dapper/SqlDataRecordHandler.cs

@@ -5,7 +5,7 @@
 #if !DNXCORE50
 namespace Dapper
 {
-    sealed class SqlDataRecordHandler : Dapper.SqlMapper.ITypeHandler
+    sealed class SqlDataRecordHandler : SqlMapper.ITypeHandler
     {
         public object Parse(Type destinationType, object value)
         {

Dapper/SqlDataRecordListTVPParameter.cs

@@ -9,7 +9,7 @@ namespace Dapper
     /// <summary>
     /// Used to pass a IEnumerable&lt;SqlDataRecord&gt; as a SqlDataRecordListTVPParameter
     /// </summary>
-    sealed class SqlDataRecordListTVPParameter : Dapper.SqlMapper.ICustomQueryParameter
+    sealed class SqlDataRecordListTVPParameter : SqlMapper.ICustomQueryParameter
     {
         private readonly IEnumerable<Microsoft.SqlServer.Server.SqlDataRecord> data;
         private readonly string typeName;

Dapper/SqlMapper.Async.cs

@@ -60,7 +60,7 @@ public static Task<IEnumerable<T>> QueryAsync<T>(this IDbConnection cnn, string
         /// </summary>
         public static Task<IEnumerable<object>> QueryAsync(this IDbConnection cnn, Type type, string sql, dynamic param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null)
         {
-            if (type == null) throw new ArgumentNullException("type");
+            if (type == null) throw new ArgumentNullException(nameof(type));
             return QueryAsync<object>(cnn, type, new CommandDefinition(sql, (object)param, transaction, commandTimeout, commandType, CommandFlags.Buffered, default(CancellationToken)));
         }
 
@@ -83,7 +83,7 @@ public static Task<IEnumerable<object>> QueryAsync(this IDbConnection cnn, Type
         private static async Task<IEnumerable<T>> QueryAsync<T>(this IDbConnection cnn, Type effectiveType, CommandDefinition command)
         {
             object param = command.Parameters;
-            var identity = new Identity(command.CommandText, command.CommandType, cnn, effectiveType, param == null ? null : param.GetType(), null);
+            var identity = new Identity(command.CommandText, command.CommandType, cnn, effectiveType, param?.GetType(), null);
             var info = GetCacheInfo(identity, param, command.AddToCache);
             bool wasClosed = cnn.State == ConnectionState.Closed;
             var cancel = command.CancellationToken;
@@ -94,7 +94,7 @@ private static async Task<IEnumerable<T>> QueryAsync<T>(this IDbConnection cnn,
                 {
                     if (wasClosed) await ((DbConnection)cnn).OpenAsync(cancel).ConfigureAwait(false);
                     reader = await cmd.ExecuteReaderAsync(wasClosed ? CommandBehavior.CloseConnection | CommandBehavior.SequentialAccess : CommandBehavior.SequentialAccess, cancel).ConfigureAwait(false);
-                    
+
                     var tuple = info.Deserializer;
                     int hash = GetColumnHash(reader);
                     if (tuple.Func == null || tuple.Hash != hash)
@@ -121,7 +121,7 @@ private static async Task<IEnumerable<T>> QueryAsync<T>(this IDbConnection cnn,
                                 buffer.Add((T)Convert.ChangeType(val, convertToType, CultureInfo.InvariantCulture));
                             }
 
-                           
+
                         }
                         while (await reader.NextResultAsync(cancel).ConfigureAwait(false)) { }
                         command.OnCompleted();
@@ -135,13 +135,13 @@ private static async Task<IEnumerable<T>> QueryAsync<T>(this IDbConnection cnn,
                         reader = null; // to prevent it being disposed before the caller gets to see it
                         return deferred;
                     }
-                    
+
                 }
                 finally
                 {
                     using (reader) { } // dispose if non-null
                     if (wasClosed) cnn.Close();
-                    
+
                 }
             }
         }
@@ -170,15 +170,15 @@ public static Task<int> ExecuteAsync(this IDbConnection cnn, CommandDefinition c
                 return ExecuteImplAsync(cnn, command, param);
             }
         }
-       
+
         private struct AsyncExecState
         {
             public readonly DbCommand Command;
             public readonly Task<int> Task;
             public AsyncExecState(DbCommand command, Task<int> task)
             {
-                this.Command = command;
-                this.Task = task;
+                Command = command;
+                Task = task;
             }
         }
         private static async Task<int> ExecuteMultiImplAsync(IDbConnection cnn, CommandDefinition command, IEnumerable multiExec)
@@ -189,7 +189,7 @@ private static async Task<int> ExecuteMultiImplAsync(IDbConnection cnn, CommandD
             try
             {
                 if (wasClosed) await ((DbConnection)cnn).OpenAsync(command.CancellationToken).ConfigureAwait(false);
-                
+
                 CacheInfo info = null;
                 string masterSql = null;
                 if ((command.Flags & CommandFlags.Pipelined) != 0)
@@ -276,7 +276,7 @@ private static async Task<int> ExecuteMultiImplAsync(IDbConnection cnn, CommandD
         }
         private static async Task<int> ExecuteImplAsync(IDbConnection cnn, CommandDefinition command, object param)
         {
-            var identity = new Identity(command.CommandText, command.CommandType, cnn, null, param == null ? null : param.GetType(), null);
+            var identity = new Identity(command.CommandText, command.CommandType, cnn, null, param?.GetType(), null);
             var info = GetCacheInfo(identity, param, command.AddToCache);
             bool wasClosed = cnn.State == ConnectionState.Closed;
             using (var cmd = (DbCommand)command.SetupCommand(cnn, info.ParamReader))
@@ -503,15 +503,15 @@ private static async Task<int> ExecuteImplAsync(IDbConnection cnn, CommandDefini
         /// <param name="commandTimeout">Number of seconds before command execution timeout</param>
         /// <param name="commandType">Is it a stored proc or a batch?</param>
         /// <returns></returns>
-        public static Task<IEnumerable<TReturn>> QueryAsync<TReturn>(this IDbConnection cnn, string sql, Type[] types, Func<object[], TReturn> map, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null) 
+        public static Task<IEnumerable<TReturn>> QueryAsync<TReturn>(this IDbConnection cnn, string sql, Type[] types, Func<object[], TReturn> map, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
         {
             var command = new CommandDefinition(sql, (object)param, transaction, commandTimeout, commandType, buffered ? CommandFlags.Buffered : CommandFlags.None, default(CancellationToken));
             return MultiMapAsync<TReturn>(cnn, command, types, map, splitOn);
         }
 
-        private static async Task<IEnumerable<TReturn>> MultiMapAsync<TReturn>(this IDbConnection cnn, CommandDefinition command, Type[] types, Func<object[], TReturn> map, string splitOn) 
+        private static async Task<IEnumerable<TReturn>> MultiMapAsync<TReturn>(this IDbConnection cnn, CommandDefinition command, Type[] types, Func<object[], TReturn> map, string splitOn)
         {
-            if (types.Length < 1) 
+            if (types.Length < 1)
             {
                 throw new ArgumentException("you must provide at least one type to deserialize");
             }
@@ -542,8 +542,7 @@ private static IEnumerable<T> ExecuteReaderSync<T>(IDataReader reader, Func<IDat
                     yield return (T)func(reader);
                 }
                 while (reader.NextResult()) { }
-                if (parameters is SqlMapper.IParameterCallbacks)
-                    ((SqlMapper.IParameterCallbacks)parameters).OnCompleted();
+                (parameters as IParameterCallbacks)?.OnCompleted();
             }
         }
 
@@ -598,7 +597,7 @@ public static async Task<GridReader> QueryMultipleAsync(this IDbConnection cnn,
                         { /* don't spoil the existing exception */ }
                     reader.Dispose();
                 }
-                if (cmd != null) cmd.Dispose();
+                cmd?.Dispose();
                 if (wasClosed) cnn.Close();
                 throw;
             }
@@ -666,7 +665,7 @@ private static async Task<IDataReader> ExecuteReaderImplAsync(IDbConnection cnn,
             finally
             {
                 if (wasClosed) cnn.Close();
-                if (cmd != null) cmd.Dispose();
+                cmd?.Dispose();
             }
         }
 
@@ -743,7 +742,7 @@ private async static Task<T> ExecuteScalarImplAsync<T>(IDbConnection cnn, Comman
             finally
             {
                 if (wasClosed) cnn.Close();
-                if (cmd != null) cmd.Dispose();
+                cmd?.Dispose();
             }
             return Parse<T>(result);
         }

Dapper/SqlMapper.DapperRow.cs

@@ -17,8 +17,8 @@ private sealed class DapperRow
 
             public DapperRow(DapperTable table, object[] values)
             {
-                if (table == null) throw new ArgumentNullException("table");
-                if (values == null) throw new ArgumentNullException("values");
+                if (table == null) throw new ArgumentNullException(nameof(table));
+                if (values == null) throw new ArgumentNullException(nameof(values));
                 this.table = table;
                 this.values = values;
             }
@@ -136,11 +136,7 @@ IEnumerator IEnumerable.GetEnumerator()
                 return dic.Remove(item.Key);
             }
 
-            bool ICollection<KeyValuePair<string, object>>.IsReadOnly
-            {
-                get { return false; }
-            }
-
+            bool ICollection<KeyValuePair<string, object>>.IsReadOnly => false;
             #endregion
 
             #region Implementation of IDictionary<string,object>
@@ -177,7 +173,7 @@ public object SetValue(string key, object value)
             }
             private object SetValue(string key, object value, bool isAdd)
             {
-                if (key == null) throw new ArgumentNullException("key");
+                if (key == null) throw new ArgumentNullException(nameof(key));
                 int index = table.IndexOfName(key);
                 if (index < 0)
                 {
@@ -186,7 +182,7 @@ private object SetValue(string key, object value, bool isAdd)
                 else if (isAdd && index < values.Length && !(values[index] is DeadValue))
                 {
                     // then semantically, this value already exists
-                    throw new ArgumentException("An item with the same key has already been added", "key");
+                    throw new ArgumentException("An item with the same key has already been added", nameof(key));
                 }
                 int oldLength = values.Length;
                 if (oldLength <= index)

Dapper/SqlMapper.DataTable.cs

@@ -10,11 +10,11 @@ private sealed class DapperTable
             string[] fieldNames;
             readonly Dictionary<string, int> fieldNameLookup;
 
-            internal string[] FieldNames { get { return fieldNames; } }
+            internal string[] FieldNames => fieldNames;
 
             public DapperTable(string[] fieldNames)
             {
-                if (fieldNames == null) throw new ArgumentNullException("fieldNames");
+                if (fieldNames == null) throw new ArgumentNullException(nameof(fieldNames));
                 this.fieldNames = fieldNames;
 
                 fieldNameLookup = new Dictionary<string, int>(fieldNames.Length, StringComparer.Ordinal);
@@ -33,7 +33,7 @@ internal int IndexOfName(string name)
             }
             internal int AddField(string name)
             {
-                if (name == null) throw new ArgumentNullException("name");
+                if (name == null) throw new ArgumentNullException(nameof(name));
                 if (fieldNameLookup.ContainsKey(name)) throw new InvalidOperationException("Field already exists: " + name);
                 int oldLen = fieldNames.Length;
                 Array.Resize(ref fieldNames, oldLen + 1); // yes, this is sub-optimal, but this is not the expected common case
@@ -48,7 +48,7 @@ internal bool FieldExists(string key)
                 return key != null && fieldNameLookup.ContainsKey(key);
             }
 
-            public int FieldCount { get { return fieldNames.Length; } }
+            public int FieldCount => fieldNames.Length;
         }
 
     }

Dapper/SqlMapper.GridReader.Async.cs

@@ -45,7 +45,7 @@ public Task<IEnumerable<dynamic>> ReadAsync(bool buffered = true)
             /// </summary>
             public Task<IEnumerable<object>> ReadAsync(Type type, bool buffered = true)
             {
-                if (type == null) throw new ArgumentNullException("type");
+                if (type == null) throw new ArgumentNullException(nameof(type));
                 return ReadAsyncImpl<object>(type, buffered);
             }
             /// <summary>
@@ -62,7 +62,7 @@ private async Task NextResultAsync()
                 {
                     readCount++;
                     gridIndex++;
-                    consumed = false;
+                    IsConsumed = false;
                 }
                 else
                 {
@@ -70,7 +70,7 @@ private async Task NextResultAsync()
                     // need for "Cancel" etc
                     reader.Dispose();
                     reader = null;
-                    if (callbacks != null) callbacks.OnCompleted();
+                    callbacks?.OnCompleted();
                     Dispose();
                 }
             }
@@ -78,7 +78,7 @@ private async Task NextResultAsync()
             private Task<IEnumerable<T>> ReadAsyncImpl<T>(Type type, bool buffered)
             {
                 if (reader == null) throw new ObjectDisposedException(GetType().FullName, "The reader has been disposed; this can happen after all data has been consumed");
-                if (consumed) throw new InvalidOperationException("Query results must be consumed in the correct order, and each result can only be consumed once");
+                if (IsConsumed) throw new InvalidOperationException("Query results must be consumed in the correct order, and each result can only be consumed once");
                 var typedIdentity = identity.ForGrid(type, gridIndex);
                 CacheInfo cache = GetCacheInfo(typedIdentity, null, addToCache);
                 var deserializer = cache.Deserializer;
@@ -89,8 +89,8 @@ private Task<IEnumerable<T>> ReadAsyncImpl<T>(Type type, bool buffered)
                     deserializer = new DeserializerState(hash, GetDeserializer(type, reader, 0, -1, false));
                     cache.Deserializer = deserializer;
                 }
-                consumed = true;
-                if (buffered && this.reader is DbDataReader)
+                IsConsumed = true;
+                if (buffered && reader is DbDataReader)
                 {
                     return ReadBufferedAsync<T>(gridIndex, deserializer.Func, typedIdentity);
                 }
@@ -104,27 +104,23 @@ private Task<IEnumerable<T>> ReadAsyncImpl<T>(Type type, bool buffered)
 
             private async Task<IEnumerable<T>> ReadBufferedAsync<T>(int index, Func<IDataReader, object> deserializer, Identity typedIdentity)
             {
-                //try
-                //{
-                var reader = (DbDataReader)this.reader;
-                List<T> buffer = new List<T>();
-                while (index == gridIndex && await reader.ReadAsync(cancel).ConfigureAwait(false))
+                try
                 {
-                    buffer.Add((T)deserializer(reader));
+                    var reader = (DbDataReader)this.reader;
+                    List<T> buffer = new List<T>();
+                    while (index == gridIndex && await reader.ReadAsync(cancel).ConfigureAwait(false))
+                    {
+                        buffer.Add((T)deserializer(reader));
+                    }
+                    return buffer;
                 }
-                if (index == gridIndex) // need to do this outside of the finally pre-C#6
+                finally // finally so that First etc progresses things even when multiple rows
                 {
-                    await NextResultAsync().ConfigureAwait(false);
+                    if (index == gridIndex)
+                    {
+                        await NextResultAsync().ConfigureAwait(false);
+                    }
                 }
-                return buffer;
-                //}
-                //finally // finally so that First etc progresses things even when multiple rows
-                //{
-                //    if (index == gridIndex)
-                //    {
-                //        await NextResultAsync().ConfigureAwait(false);
-                //    }
-                //}
             }
         }
 

Dapper/SqlMapper.GridReader.cs

@@ -22,18 +22,17 @@ partial class SqlMapper
     {
 
         /// <summary>
-        /// The grid reader provides interfaces for reading multiple result sets from a Dapper query 
+        /// The grid reader provides interfaces for reading multiple result sets from a Dapper query
         /// </summary>
         public partial class GridReader : IDisposable
         {
             private IDataReader reader;
-            private IDbCommand command;
             private Identity identity;
             private bool addToCache;
 
-            internal GridReader(IDbCommand command, IDataReader reader, Identity identity, SqlMapper.IParameterCallbacks callbacks, bool addToCache)
+            internal GridReader(IDbCommand command, IDataReader reader, Identity identity, IParameterCallbacks callbacks, bool addToCache)
             {
-                this.Command = command;
+                Command = command;
                 this.reader = reader;
                 this.identity = identity;
                 this.callbacks = callbacks;
@@ -62,14 +61,14 @@ public IEnumerable<T> Read<T>(bool buffered = true)
             /// </summary>
             public IEnumerable<object> Read(Type type, bool buffered = true)
             {
-                if (type == null) throw new ArgumentNullException("type");
+                if (type == null) throw new ArgumentNullException(nameof(type));
                 return ReadImpl<object>(type, buffered);
             }
 
             private IEnumerable<T> ReadImpl<T>(Type type, bool buffered)
             {
                 if (reader == null) throw new ObjectDisposedException(GetType().FullName, "The reader has been disposed; this can happen after all data has been consumed");
-                if (consumed) throw new InvalidOperationException("Query results must be consumed in the correct order, and each result can only be consumed once");
+                if (IsConsumed) throw new InvalidOperationException("Query results must be consumed in the correct order, and each result can only be consumed once");
                 var typedIdentity = identity.ForGrid(type, gridIndex);
                 CacheInfo cache = GetCacheInfo(typedIdentity, null, addToCache);
                 var deserializer = cache.Deserializer;
@@ -80,7 +79,7 @@ private IEnumerable<T> ReadImpl<T>(Type type, bool buffered)
                     deserializer = new DeserializerState(hash, GetDeserializer(type, reader, 0, -1, false));
                     cache.Deserializer = deserializer;
                 }
-                consumed = true;
+                IsConsumed = true;
                 var result = ReadDeferred<T>(gridIndex, deserializer.Func, typedIdentity);
                 return buffered ? result.ToList() : result;
             }
@@ -99,7 +98,7 @@ private IEnumerable<T> ReadImpl<T>(Type type, bool buffered)
                 }, gridIndex);
                 try
                 {
-                    foreach (var r in SqlMapper.MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(null, default(CommandDefinition), func, splitOn, reader, identity, false))
+                    foreach (var r in MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(null, default(CommandDefinition), func, splitOn, reader, identity, false))
                     {
                         yield return r;
                     }
@@ -115,7 +114,7 @@ private IEnumerable<TReturn> MultiReadInternal<TReturn>(Type[] types, Func<objec
                 var identity = this.identity.ForGrid(typeof(TReturn), types, gridIndex);
                 try
                 {
-                    foreach (var r in SqlMapper.MultiMapImpl<TReturn>(null, default(CommandDefinition), types, map, splitOn, reader, identity, false))
+                    foreach (var r in MultiMapImpl<TReturn>(null, default(CommandDefinition), types, map, splitOn, reader, identity, false))
                     {
                         yield return r;
                     }
@@ -205,34 +204,17 @@ private IEnumerable<T> ReadDeferred<T>(int index, Func<IDataReader, object> dese
                 }
             }
             private int gridIndex, readCount;
-            private bool consumed;
-            private SqlMapper.IParameterCallbacks callbacks;
+            private IParameterCallbacks callbacks;
 
             /// <summary>
             /// Has the underlying reader been consumed?
             /// </summary>
-            public bool IsConsumed
-            {
-                get
-                {
-                    return consumed;
-                }
-            }
+            public bool IsConsumed { get; private set; }
+
             /// <summary>
             /// The command associated with the reader
             /// </summary>
-            public IDbCommand Command
-            {
-                get
-                {
-                    return command;
-                }
-
-                set
-                {
-                    command = value;
-                }
-            }
+            public IDbCommand Command { get; set; }
 
             private void NextResult()
             {
@@ -240,7 +222,7 @@ private void NextResult()
                 {
                     readCount++;
                     gridIndex++;
-                    consumed = false;
+                    IsConsumed = false;
                 }
                 else
                 {
@@ -248,7 +230,7 @@ private void NextResult()
                     // need for "Cancel" etc
                     reader.Dispose();
                     reader = null;
-                    if (callbacks != null) callbacks.OnCompleted();
+                    callbacks?.OnCompleted();
                     Dispose();
                 }
             }
@@ -259,7 +241,7 @@ public void Dispose()
             {
                 if (reader != null)
                 {
-                    if (!reader.IsClosed && Command != null) Command.Cancel();
+                    if (!reader.IsClosed) Command?.Cancel();
                     reader.Dispose();
                     reader = null;
                 }

Dapper/SqlMapper.Identity.cs

@@ -58,22 +58,22 @@ private Identity(string sql, CommandType? commandType, string connectionString,
                     hashCode = 17; // we *know* we are using this in a dictionary, so pre-compute this
                     hashCode = hashCode * 23 + commandType.GetHashCode();
                     hashCode = hashCode * 23 + gridIndex.GetHashCode();
-                    hashCode = hashCode * 23 + (sql == null ? 0 : sql.GetHashCode());
-                    hashCode = hashCode * 23 + (type == null ? 0 : type.GetHashCode());
+                    hashCode = hashCode * 23 + (sql?.GetHashCode() ?? 0);
+                    hashCode = hashCode * 23 + (type?.GetHashCode() ?? 0);
                     if (otherTypes != null)
                     {
                         foreach (var t in otherTypes)
                         {
-                            hashCode = hashCode * 23 + (t == null ? 0 : t.GetHashCode());
+                            hashCode = hashCode * 23 + (t?.GetHashCode() ?? 0);
                         }
                     }
-                    hashCode = hashCode * 23 + (connectionString == null ? 0 : SqlMapper.connectionStringComparer.GetHashCode(connectionString));
-                    hashCode = hashCode * 23 + (parametersType == null ? 0 : parametersType.GetHashCode());
+                    hashCode = hashCode * 23 + (connectionString == null ? 0 : connectionStringComparer.GetHashCode(connectionString));
+                    hashCode = hashCode * 23 + (parametersType?.GetHashCode() ?? 0);
                 }
             }
 
             /// <summary>
-            /// 
+            ///
             /// </summary>
             /// <param name="obj"></param>
             /// <returns></returns>
@@ -86,28 +86,28 @@ public override bool Equals(object obj)
             /// </summary>
             public readonly string sql;
             /// <summary>
-            /// The command type 
+            /// The command type
             /// </summary>
             public readonly CommandType? commandType;
 
             /// <summary>
-            /// 
+            ///
             /// </summary>
             public readonly int hashCode, gridIndex;
             /// <summary>
-            /// 
+            ///
             /// </summary>
             public readonly Type type;
             /// <summary>
-            /// 
+            ///
             /// </summary>
             public readonly string connectionString;
             /// <summary>
-            /// 
+            ///
             /// </summary>
             public readonly Type parametersType;
             /// <summary>
-            /// 
+            ///
             /// </summary>
             /// <returns></returns>
             public override int GetHashCode()
@@ -127,7 +127,7 @@ public bool Equals(Identity other)
                     type == other.type &&
                     sql == other.sql &&
                     commandType == other.commandType &&
-                    SqlMapper.connectionStringComparer.Equals(connectionString, other.connectionString) &&
+                    connectionStringComparer.Equals(connectionString, other.connectionString) &&
                     parametersType == other.parametersType;
             }
         }

Dapper/SqlMapper.Link.cs

@@ -49,9 +49,9 @@ private Link(TKey key, TValue value, Link<TKey, TValue> tail)
                 Value = value;
                 Tail = tail;
             }
-            public TKey Key { get; private set; }
-            public TValue Value { get; private set; }
-            public Link<TKey, TValue> Tail { get; private set; }
+            public TKey Key { get; }
+            public TValue Value { get; }
+            public Link<TKey, TValue> Tail { get; }
         }
     }
 }

Dapper/SqlMapper.LiteralToken.cs

@@ -9,20 +9,20 @@ partial class SqlMapper
         /// </summary>
         internal struct LiteralToken
         {
-            private readonly string token, member;
             /// <summary>
             /// The text in the original command that should be replaced
             /// </summary>
-            public string Token { get { return token; } }
+            public string Token { get; }
 
             /// <summary>
             /// The name of the member referred to by the token
             /// </summary>
-            public string Member { get { return member; } }
+            public string Member { get; }
+
             internal LiteralToken(string token, string member)
             {
-                this.token = token;
-                this.member = member;
+                Token = token;
+                Member = member;
             }
 
             internal static readonly IList<LiteralToken> None = new LiteralToken[0];

Dapper/SqlMapper.cs

 /*
- License: http://www.apache.org/licenses/LICENSE-2.0 
+ License: http://www.apache.org/licenses/LICENSE-2.0
  Home page: http://code.google.com/p/dapper-dot-net/
  */
 
@@ -47,7 +47,7 @@ static int GetColumnHash(IDataReader reader)
                 for (int i = 0; i < colCount; i++)
                 {   // binding code is only interested in names - not types
                     object tmp = reader.GetName(i);
-                    hash = (hash * 31) + (tmp == null ? 0 : tmp.GetHashCode());
+                    hash = (hash * 31) + (tmp?.GetHashCode() ?? 0);
                 }
                 return hash;
             }
@@ -61,7 +61,7 @@ static int GetColumnHash(IDataReader reader)
         private static void OnQueryCachePurged()
         {
             var handler = QueryCachePurged;
-            if (handler != null) handler(null, EventArgs.Empty);
+            handler?.Invoke(null, EventArgs.Empty);
         }
 
         static readonly System.Collections.Concurrent.ConcurrentDictionary<Identity, CacheInfo> _queryCache = new System.Collections.Concurrent.ConcurrentDictionary<Identity, CacheInfo>();
@@ -108,7 +108,7 @@ private static bool TryGetQueryCache(Identity key, out CacheInfo value)
         }
 
         /// <summary>
-        /// Purge the query cache 
+        /// Purge the query cache
         /// </summary>
         public static void PurgeQueryCache()
         {
@@ -177,44 +177,46 @@ public static int GetCachedSQLCount()
 
         static SqlMapper()
         {
-            typeMap = new Dictionary<Type, DbType>();
-            typeMap[typeof(byte)] = DbType.Byte;
-            typeMap[typeof(sbyte)] = DbType.SByte;
-            typeMap[typeof(short)] = DbType.Int16;
-            typeMap[typeof(ushort)] = DbType.UInt16;
-            typeMap[typeof(int)] = DbType.Int32;
-            typeMap[typeof(uint)] = DbType.UInt32;
-            typeMap[typeof(long)] = DbType.Int64;
-            typeMap[typeof(ulong)] = DbType.UInt64;
-            typeMap[typeof(float)] = DbType.Single;
-            typeMap[typeof(double)] = DbType.Double;
-            typeMap[typeof(decimal)] = DbType.Decimal;
-            typeMap[typeof(bool)] = DbType.Boolean;
-            typeMap[typeof(string)] = DbType.String;
-            typeMap[typeof(char)] = DbType.StringFixedLength;
-            typeMap[typeof(Guid)] = DbType.Guid;
-            typeMap[typeof(DateTime)] = DbType.DateTime;
-            typeMap[typeof(DateTimeOffset)] = DbType.DateTimeOffset;
-            typeMap[typeof(TimeSpan)] = DbType.Time;
-            typeMap[typeof(byte[])] = DbType.Binary;
-            typeMap[typeof(byte?)] = DbType.Byte;
-            typeMap[typeof(sbyte?)] = DbType.SByte;
-            typeMap[typeof(short?)] = DbType.Int16;
-            typeMap[typeof(ushort?)] = DbType.UInt16;
-            typeMap[typeof(int?)] = DbType.Int32;
-            typeMap[typeof(uint?)] = DbType.UInt32;
-            typeMap[typeof(long?)] = DbType.Int64;
-            typeMap[typeof(ulong?)] = DbType.UInt64;
-            typeMap[typeof(float?)] = DbType.Single;
-            typeMap[typeof(double?)] = DbType.Double;
-            typeMap[typeof(decimal?)] = DbType.Decimal;
-            typeMap[typeof(bool?)] = DbType.Boolean;
-            typeMap[typeof(char?)] = DbType.StringFixedLength;
-            typeMap[typeof(Guid?)] = DbType.Guid;
-            typeMap[typeof(DateTime?)] = DbType.DateTime;
-            typeMap[typeof(DateTimeOffset?)] = DbType.DateTimeOffset;
-            typeMap[typeof(TimeSpan?)] = DbType.Time;
-            typeMap[typeof(object)] = DbType.Object;
+            typeMap = new Dictionary<Type, DbType>
+                      {
+                          [typeof(byte)] = DbType.Byte,
+                          [typeof(sbyte)] = DbType.SByte,
+                          [typeof(short)] = DbType.Int16,
+                          [typeof(ushort)] = DbType.UInt16,
+                          [typeof(int)] = DbType.Int32,
+                          [typeof(uint)] = DbType.UInt32,
+                          [typeof(long)] = DbType.Int64,
+                          [typeof(ulong)] = DbType.UInt64,
+                          [typeof(float)] = DbType.Single,
+                          [typeof(double)] = DbType.Double,
+                          [typeof(decimal)] = DbType.Decimal,
+                          [typeof(bool)] = DbType.Boolean,
+                          [typeof(string)] = DbType.String,
+                          [typeof(char)] = DbType.StringFixedLength,
+                          [typeof(Guid)] = DbType.Guid,
+                          [typeof(DateTime)] = DbType.DateTime,
+                          [typeof(DateTimeOffset)] = DbType.DateTimeOffset,
+                          [typeof(TimeSpan)] = DbType.Time,
+                          [typeof(byte[])] = DbType.Binary,
+                          [typeof(byte?)] = DbType.Byte,
+                          [typeof(sbyte?)] = DbType.SByte,
+                          [typeof(short?)] = DbType.Int16,
+                          [typeof(ushort?)] = DbType.UInt16,
+                          [typeof(int?)] = DbType.Int32,
+                          [typeof(uint?)] = DbType.UInt32,
+                          [typeof(long?)] = DbType.Int64,
+                          [typeof(ulong?)] = DbType.UInt64,
+                          [typeof(float?)] = DbType.Single,
+                          [typeof(double?)] = DbType.Double,
+                          [typeof(decimal?)] = DbType.Decimal,
+                          [typeof(bool?)] = DbType.Boolean,
+                          [typeof(char?)] = DbType.StringFixedLength,
+                          [typeof(Guid?)] = DbType.Guid,
+                          [typeof(DateTime?)] = DbType.DateTime,
+                          [typeof(DateTimeOffset?)] = DbType.DateTimeOffset,
+                          [typeof(TimeSpan?)] = DbType.Time,
+                          [typeof(object)] = DbType.Object
+                      };
 #if !DNXCORE50
             AddTypeHandlerImpl(typeof(DataTable), new DataTableHandler(), false);
             AddTypeHandlerImpl(typeof(IEnumerable<Microsoft.SqlServer.Server.SqlDataRecord>), new SqlDataRecordHandler(), false);
@@ -243,8 +245,7 @@ public static void AddTypeMap(Type type, DbType dbType)
             DbType oldValue;
             if (snapshot.TryGetValue(type, out oldValue) && oldValue == dbType) return; // nothing to do
 
-            var newCopy = new Dictionary<Type, DbType>(snapshot);
-            newCopy[type] = dbType;
+            var newCopy = new Dictionary<Type, DbType>(snapshot) { [type] = dbType };
             typeMap = newCopy;
         }
 
@@ -261,7 +262,7 @@ public static void AddTypeHandler(Type type, ITypeHandler handler)
         /// </summary>
         public static void AddTypeHandlerImpl(Type type, ITypeHandler handler, bool clone)
         {
-            if (type == null) throw new ArgumentNullException("type");
+            if (type == null) throw new ArgumentNullException(nameof(type));
 
             Type secondary = null;
             if(type.IsValueType())
@@ -377,7 +378,7 @@ internal static DbType LookupDbType(Type type, string name, bool demand, out ITy
             }
 #endif
             if(demand)
-                throw new NotSupportedException(string.Format("The member {0} of type {1} cannot be used as a parameter value", name, type.FullName));
+                throw new NotSupportedException($"The member {name} of type {type.FullName} cannot be used as a parameter value");
             return DbType.Object;
 
         }
@@ -394,7 +395,7 @@ public static List<T> AsList<T>(this IEnumerable<T> source)
         }
 
         /// <summary>
-        /// Execute parameterized SQL  
+        /// Execute parameterized SQL
         /// </summary>
         /// <returns>Number of rows affected</returns>
         public static int Execute(
@@ -405,7 +406,7 @@ public static List<T> AsList<T>(this IEnumerable<T> source)
             return ExecuteImpl(cnn, ref command);
         }
         /// <summary>
-        /// Execute parameterized SQL  
+        /// Execute parameterized SQL
         /// </summary>
         /// <returns>Number of rows affected</returns>
         public static int Execute(this IDbConnection cnn, CommandDefinition command)
@@ -617,7 +618,7 @@ public static IEnumerable<dynamic> Query(this IDbConnection cnn, string sql, obj
             this IDbConnection cnn, Type type, string sql, object param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null
         )
         {
-            if (type == null) throw new ArgumentNullException("type");
+            if (type == null) throw new ArgumentNullException(nameof(type));
             var command = new CommandDefinition(sql, (object)param, transaction, commandTimeout, commandType, buffered ? CommandFlags.Buffered : CommandFlags.None);
             var data = QueryImpl<object>(cnn, command, type);
             return command.Buffered ? data.ToList() : data;
@@ -657,7 +658,7 @@ public static GridReader QueryMultiple(this IDbConnection cnn, CommandDefinition
         private static GridReader QueryMultipleImpl(this IDbConnection cnn, ref CommandDefinition command)
         {
             object param = command.Parameters;
-            Identity identity = new Identity(command.CommandText, command.CommandType, cnn, typeof(GridReader), param == null ? null : param.GetType(), null);
+            Identity identity = new Identity(command.CommandText, command.CommandType, cnn, typeof(GridReader), param?.GetType(), null);
             CacheInfo info = GetCacheInfo(identity, param, command.AddToCache);
 
             IDbCommand cmd = null;
@@ -681,11 +682,11 @@ private static GridReader QueryMultipleImpl(this IDbConnection cnn, ref CommandD
             {
                 if (reader != null)
                 {
-                    if (!reader.IsClosed) try { cmd.Cancel(); }
+                    if (!reader.IsClosed) try { cmd?.Cancel(); }
                         catch { /* don't spoil the existing exception */ }
                     reader.Dispose();
                 }
-                if (cmd != null) cmd.Dispose();
+                cmd?.Dispose();
                 if (wasClosed) cnn.Close();
                 throw;
             }
@@ -694,7 +695,7 @@ private static GridReader QueryMultipleImpl(this IDbConnection cnn, ref CommandD
         private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefinition command, Type effectiveType)
         {
             object param = command.Parameters;
-            var identity = new Identity(command.CommandText, command.CommandType, cnn, effectiveType, param == null ? null : param.GetType(), null);
+            var identity = new Identity(command.CommandText, command.CommandType, cnn, effectiveType, param?.GetType(), null);
             var info = GetCacheInfo(identity, param, command.AddToCache);
 
             IDbCommand cmd = null;
@@ -749,7 +750,7 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
                     reader.Dispose();
                 }
                 if (wasClosed) cnn.Close();
-                if (cmd != null) cmd.Dispose();
+                cmd?.Dispose();
             }
         }
 
@@ -938,7 +939,7 @@ public static IEnumerable<TReturn> Query<TReturn>(this IDbConnection cnn, string
         static IEnumerable<TReturn> MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(this IDbConnection cnn, CommandDefinition command, Delegate map, string splitOn, IDataReader reader, Identity identity, bool finalize)
         {
             object param = command.Parameters;
-            identity = identity ?? new Identity(command.CommandText, command.CommandType, cnn, typeof(TFirst), param == null ? null : param.GetType(), new[] { typeof(TFirst), typeof(TSecond), typeof(TThird), typeof(TFourth), typeof(TFifth), typeof(TSixth), typeof(TSeventh) });
+            identity = identity ?? new Identity(command.CommandText, command.CommandType, cnn, typeof(TFirst), param?.GetType(), new[] { typeof(TFirst), typeof(TSecond), typeof(TThird), typeof(TFourth), typeof(TFifth), typeof(TSixth), typeof(TSeventh) });
             CacheInfo cinfo = GetCacheInfo(identity, param, command.AddToCache);
 
             IDbCommand ownedCommand = null;
@@ -978,24 +979,18 @@ public static IEnumerable<TReturn> Query<TReturn>(this IDbConnection cnn, string
                     {
                         while (reader.NextResult()) { }
                         command.OnCompleted();
-                    }                    
+                    }
                 }
             }
             finally
             {
                 try
                 {
-                    if (ownedReader != null)
-                    {
-                        ownedReader.Dispose();
-                    }
+                    ownedReader?.Dispose();
                 }
                 finally
                 {
-                    if (ownedCommand != null)
-                    {
-                        ownedCommand.Dispose();
-                    }
+                    ownedCommand?.Dispose();
                     if (wasClosed) cnn.Close();
                 }
             }
@@ -1056,17 +1051,11 @@ static IEnumerable<TReturn> MultiMapImpl<TReturn>(this IDbConnection cnn, Comman
             {
                 try
                 {
-                    if (ownedReader != null)
-                    {
-                        ownedReader.Dispose();
-                    }
+                    ownedReader?.Dispose();
                 }
                 finally
                 {
-                    if (ownedCommand != null)
-                    {
-                        ownedCommand.Dispose();
-                    }
+                    ownedCommand?.Dispose();
                     if (wasClosed) cnn.Close();
                 }
             }
@@ -1272,7 +1261,7 @@ private static void PassByPosition(IDbCommand cmd)
             if (cmd.Parameters.Count == 0) return;
 
             Dictionary<string, IDbDataParameter> parameters = new Dictionary<string, IDbDataParameter>(StringComparer.Ordinal);
-            
+
             foreach(IDbDataParameter param in cmd.Parameters)
             {
                 if (!string.IsNullOrEmpty(param.ParameterName)) parameters[param.ParameterName] = param;
@@ -1348,7 +1337,7 @@ private static Exception MultiMapException(IDataRecord reader)
             else
                 return new InvalidOperationException("No columns were selected");
         }
-        
+
         internal static Func<IDataReader, object> GetDapperRowDeserializer(IDataRecord reader, int startBound, int length, bool returnNullIfFirstMissing)
         {
             var fieldCount = reader.FieldCount;
@@ -1422,9 +1411,9 @@ private static Exception MultiMapException(IDataRecord reader)
         [Obsolete("This method is for internal usage only", false)]
         public static char ReadChar(object value)
         {
-            if (value == null || value is DBNull) throw new ArgumentNullException("value");
+            if (value == null || value is DBNull) throw new ArgumentNullException(nameof(value));
             string s = value as string;
-            if (s == null || s.Length != 1) throw new ArgumentException("A single-character was expected", "value");
+            if (s == null || s.Length != 1) throw new ArgumentException("A single-character was expected", nameof(value));
             return s[0];
         }
 
@@ -1440,7 +1429,7 @@ public static char ReadChar(object value)
         {
             if (value == null || value is DBNull) return null;
             string s = value as string;
-            if (s == null || s.Length != 1) throw new ArgumentException("A single-character was expected", "value");
+            if (s == null || s.Length != 1) throw new ArgumentException("A single-character was expected", nameof(value));
             return s[0];
         }
 
@@ -1550,7 +1539,7 @@ public static void PackListParameters(IDbCommand command, string namePrefix, obj
                         {
                             return "(SELECT " + variableName + " WHERE 1 = 0)";
                         }
-                    }, RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.CultureInvariant);                        
+                    }, RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.CultureInvariant);
                     var dummyParam = command.CreateParameter();
                     dummyParam.ParameterName = namePrefix;
                     dummyParam.Value = DBNull.Value;
@@ -1565,7 +1554,7 @@ public static void PackListParameters(IDbCommand command, string namePrefix, obj
                         {
                             // looks like an optimize hint; expand it
                             var suffix = match.Groups[2].Value;
-                                
+
                             var sb = GetStringBuilder().Append(variableName).Append(1).Append(suffix);
                             for (int i = 2; i <= count; i++)
                             {
@@ -1757,13 +1746,13 @@ internal static IList<LiteralToken> GetLiteralTokens(string sql)
         internal static Action<IDbCommand, object> CreateParamInfoGenerator(Identity identity, bool checkForDuplicates, bool removeUnused, IList<LiteralToken> literals)
         {
             Type type = identity.parametersType;
-            
+
             bool filterParams = false;
             if (removeUnused && identity.commandType.GetValueOrDefault(CommandType.Text) == CommandType.Text)
             {
                 filterParams = !smellsLikeOleDb.IsMatch(identity.sql);
             }
-            var dm = new DynamicMethod(string.Format("ParamInfo{0}", Guid.NewGuid()), null, new[] { typeof(IDbCommand), typeof(object) }, type, true);
+            var dm = new DynamicMethod($"ParamInfo{Guid.NewGuid()}", null, new[] { typeof(IDbCommand), typeof(object) }, type, true);
 
             var il = dm.GetILGenerator();
 
@@ -1958,7 +1947,7 @@ internal static IList<LiteralToken> GetLiteralTokens(string sql)
                         il.MarkLabel(isLong);
                         EmitInt32(il, -1); // [string] [-1]
                         il.MarkLabel(lenDone);
-                        il.Emit(OpCodes.Stloc_1); // [string] 
+                        il.Emit(OpCodes.Stloc_1); // [string]
                     }
                     if (prop.PropertyType.FullName == LinqBinary)
                     {
@@ -2134,7 +2123,7 @@ private static int ExecuteCommand(IDbConnection cnn, ref CommandDefinition comma
             finally
             {
                 if (wasClosed) cnn.Close();
-                if (cmd != null) cmd.Dispose();
+                cmd?.Dispose();
             }
         }
 
@@ -2161,7 +2150,7 @@ private static T ExecuteScalarImpl<T>(IDbConnection cnn, ref CommandDefinition c
             finally
             {
                 if (wasClosed) cnn.Close();
-                if (cmd != null) cmd.Dispose();
+                cmd?.Dispose();
             }
             return Parse<T>(result);
         }
@@ -2205,7 +2194,7 @@ private static IDataReader ExecuteReaderImpl(IDbConnection cnn, ref CommandDefin
                 var identity = new Identity(command.CommandText, command.CommandType, cnn, null, param.GetType(), null);
                 info = GetCacheInfo(identity, param, command.AddToCache);
             }
-            var paramReader = info == null ? null : info.ParamReader;
+            var paramReader = info?.ParamReader;
             return paramReader;
         }
 
@@ -2215,11 +2204,11 @@ private static IDataReader ExecuteReaderImpl(IDbConnection cnn, ref CommandDefin
 #pragma warning disable 618
             if (type == typeof(char))
             { // this *does* need special handling, though
-                return r => SqlMapper.ReadChar(r.GetValue(index));
+                return r => ReadChar(r.GetValue(index));
             }
             if (type == typeof(char?))
             {
-                return r => SqlMapper.ReadNullableChar(r.GetValue(index));
+                return r => ReadNullableChar(r.GetValue(index));
             }
             if (type.FullName == LinqBinary)
             {
@@ -2295,7 +2284,7 @@ static readonly MethodInfo
         /// <returns>Type map implementation, DefaultTypeMap instance if no override present</returns>
         public static ITypeMap GetTypeMap(Type type)
         {
-            if (type == null) throw new ArgumentNullException("type");
+            if (type == null) throw new ArgumentNullException(nameof(type));
 #if DNXCORE50
             ITypeMap map = null;
 #else
@@ -2337,7 +2326,7 @@ public static ITypeMap GetTypeMap(Type type)
         public static void SetTypeMap(Type type, ITypeMap map)
         {
             if (type == null)
-                throw new ArgumentNullException("type");
+                throw new ArgumentNullException(nameof(type));
 
             if (map == null || map is DefaultTypeMap)
             {
@@ -2371,7 +2360,7 @@ public static void SetTypeMap(Type type, ITypeMap map)
         )
         {
 
-            var dm = new DynamicMethod(string.Format("Deserialize{0}", Guid.NewGuid()), typeof(object), new[] { typeof(IDataReader) }, true);
+            var dm = new DynamicMethod($"Deserialize{Guid.NewGuid()}", typeof(object), new[] { typeof(IDataReader) }, true);
             var il = dm.GetILGenerator();
             il.DeclareLocal(typeof(int));
             il.DeclareLocal(type);
@@ -2455,8 +2444,8 @@ public static void SetTypeMap(Type type, ITypeMap map)
                     var ctor = typeMap.FindConstructor(names, types);
                     if (ctor == null)
                     {
-                        string proposedTypes = "(" + string.Join(", ", types.Select((t, i) => t.FullName + " " + names[i]).ToArray()) + ")";
-                        throw new InvalidOperationException(string.Format("A parameterless default constructor or one matching signature {0} is required for {1} materialization", proposedTypes, type.FullName));
+                        string proposedTypes = $"({string.Join(", ", types.Select((t, i) => t.FullName + " " + names[i]).ToArray())})";
+                        throw new InvalidOperationException($"A parameterless default constructor or one matching signature {proposedTypes} is required for {type.FullName} materialization");
                     }
 
                     if (ctor.GetParameters().Length == 0)
@@ -2762,7 +2751,7 @@ private static void FlexibleConvertBoxedFromHeadOfStack(ILGenerator il, Type fro
                     il.EmitCall(OpCodes.Call, typeof(Convert).GetMethod("ChangeType", new Type[] { typeof(object), typeof(Type) }), null); // stack is now [target][target][boxed-member-type-value]
                     il.Emit(OpCodes.Unbox_Any, to); // stack is now [target][target][typed-value]
                 }
-            }            
+            }
         }
 
         static MethodInfo GetOperator(Type from, Type to)
@@ -2789,7 +2778,7 @@ static MethodInfo ResolveOperator(MethodInfo[] methods, Type from, Type to, stri
 
         private static void LoadLocal(ILGenerator il, int index)
         {
-            if (index < 0 || index >= short.MaxValue) throw new ArgumentNullException("index");
+            if (index < 0 || index >= short.MaxValue) throw new ArgumentNullException(nameof(index));
             switch (index)
             {
                 case 0: il.Emit(OpCodes.Ldloc_0); break;
@@ -2810,7 +2799,7 @@ private static void LoadLocal(ILGenerator il, int index)
         }
         private static void StoreLocal(ILGenerator il, int index)
         {
-            if (index < 0 || index >= short.MaxValue) throw new ArgumentNullException("index");
+            if (index < 0 || index >= short.MaxValue) throw new ArgumentNullException(nameof(index));
             switch (index)
             {
                 case 0: il.Emit(OpCodes.Stloc_0); break;
@@ -2831,7 +2820,7 @@ private static void StoreLocal(ILGenerator il, int index)
         }
         private static void LoadLocalAddress(ILGenerator il, int index)
         {
-            if (index < 0 || index >= short.MaxValue) throw new ArgumentNullException("index");
+            if (index < 0 || index >= short.MaxValue) throw new ArgumentNullException(nameof(index));
 
             if (index <= 255)
             {
@@ -2871,7 +2860,7 @@ public static void ThrowDataException(Exception ex, int index, IDataReader reade
                         formattedValue = valEx.Message;
                     }
                 }
-                toThrow = new DataException(string.Format("Error parsing column {0} ({1}={2})", index, name, formattedValue), ex);
+                toThrow = new DataException($"Error parsing column {index} ({name}={formattedValue})", ex);
             }
             catch
             { // throw the **original** exception, wrapped as DataException
@@ -2956,7 +2945,7 @@ public static void SetTypeName(this DataTable table, string typeName)
         /// </summary>
         public static string GetTypeName(this DataTable table)
         {
-            return table == null ? null : table.ExtendedProperties[DataTableTypeNameKey] as string;
+            return table?.ExtendedProperties[DataTableTypeNameKey] as string;
         }
 
         /// <summary>

Dapper/TableValuedParameter.cs

@@ -8,7 +8,7 @@ namespace Dapper
     /// <summary>
     /// Used to pass a DataTable as a TableValuedParameter
     /// </summary>
-    sealed class TableValuedParameter : Dapper.SqlMapper.ICustomQueryParameter
+    sealed class TableValuedParameter : SqlMapper.ICustomQueryParameter
     {
         private readonly DataTable table;
         private readonly string typeName;
@@ -47,14 +47,14 @@ internal static void Set(IDbDataParameter parameter, DataTable table, string typ
             parameter.Value = SqlMapper.SanitizeParameterValue(table);
             if (string.IsNullOrEmpty(typeName) && table != null)
             {
-                typeName = SqlMapper.GetTypeName(table);
+                typeName = table.GetTypeName();
             }
             if (!string.IsNullOrEmpty(typeName))
             {
                 var sqlParam = parameter as System.Data.SqlClient.SqlParameter;
                 if (sqlParam != null)
                 {
-                    if (setTypeName != null) setTypeName(sqlParam, typeName);
+                    setTypeName?.Invoke(sqlParam, typeName);
                     sqlParam.SqlDbType = SqlDbType.Structured;
                 }
             }

Dapper/WrappedReader.cs

@@ -252,23 +252,17 @@ public WrappedReader(IDbCommand cmd, IDataReader reader)
 
         void IDataReader.Close()
         {
-            if (reader != null) reader.Close();
+            reader?.Close();
         }
 
-        int IDataReader.Depth
-        {
-            get { return Reader.Depth; }
-        }
+        int IDataReader.Depth => Reader.Depth;
 
         DataTable IDataReader.GetSchemaTable()
         {
             return Reader.GetSchemaTable();
         }
 
-        bool IDataReader.IsClosed
-        {
-            get { return reader == null ? true : reader.IsClosed; }
-        }
+        bool IDataReader.IsClosed => reader?.IsClosed ?? true;
 
         bool IDataReader.NextResult()
         {
@@ -280,24 +274,18 @@ bool IDataReader.Read()
             return Reader.Read();
         }
 
-        int IDataReader.RecordsAffected
-        {
-            get { return Reader.RecordsAffected; }
-        }
+        int IDataReader.RecordsAffected => Reader.RecordsAffected;
 
         void IDisposable.Dispose()
         {
-            if (reader != null) reader.Close();
-            if (reader != null) reader.Dispose();
+            reader?.Close();
+            reader?.Dispose();
             reader = null;
-            if (cmd != null) cmd.Dispose();
+            cmd?.Dispose();
             cmd = null;
         }
 
-        int IDataRecord.FieldCount
-        {
-            get { return Reader.FieldCount; }
-        }
+        int IDataRecord.FieldCount => Reader.FieldCount;
 
         bool IDataRecord.GetBoolean(int i)
         {
@@ -409,15 +397,9 @@ bool IDataRecord.IsDBNull(int i)
             return Reader.IsDBNull(i);
         }
 
-        object IDataRecord.this[string name]
-        {
-            get { return Reader[name]; }
-        }
+        object IDataRecord.this[string name] => Reader[name];
 
-        object IDataRecord.this[int i]
-        {
-            get { return Reader[i]; }
-        }
+        object IDataRecord.this[int i] => Reader[i];
     }
 #endif
 }