Fix list handling when using dynamic parameters; see http://stackoverflow.com/q/12723922/23354

Dapper/SqlMapper.cs

@@ -408,7 +408,7 @@ static SqlMapper()
         }
 
         internal const string LinqBinary = "System.Data.Linq.Binary";
-        private static DbType LookupDbType(Type type, string name)
+        internal static DbType LookupDbType(Type type, string name)
         {
             DbType dbType;
             var nullUnderlyingType = Nullable.GetUnderlyingType(type);
@@ -1394,7 +1394,7 @@ public static IDbDataParameter FindOrAddParameter(IDataParameterCollection param
         /// Internal use only
         /// </summary>
         [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
-        [Obsolete("This method is for internal usage only", true)]
+        [Obsolete("This method is for internal usage only", false)]
         public static void PackListParameters(IDbCommand command, string namePrefix, object value)
         {
             // initially we tried TVP, however it performs quite poorly.
@@ -2572,18 +2572,33 @@ protected void AddParameters(IDbCommand command, SqlMapper.Identity identity)
 
             foreach (var param in parameters.Values)
             {
+                var dbType = param.DbType;
+                var val = param.Value;
                 string name = Clean(param.Name);
+
+                if (dbType == null && val != null) dbType = SqlMapper.LookupDbType(val.GetType(), name);
+
+                if (dbType == DbType.Xml)
+                { // actually represents "in" lists
+#pragma warning disable 612, 618
+                    SqlMapper.PackListParameters(command, name, val);
+#pragma warning restore 612, 618
+                }
+                else
+                {
+
                     bool add = !command.Parameters.Contains(name);
                     IDbDataParameter p;
-                if(add)
+                    if (add)
                     {
                         p = command.CreateParameter();
                         p.ParameterName = name;
-                } else
+                    }
+                    else
                     {
                         p = (IDbDataParameter)command.Parameters[name];
                     }
-                var val = param.Value;
+
                     p.Value = val ?? DBNull.Value;
                     p.Direction = param.ParameterDirection;
                     var s = val as string;
@@ -2598,9 +2613,9 @@ protected void AddParameters(IDbCommand command, SqlMapper.Identity identity)
                     {
                         p.Size = param.Size.Value;
                     }
-                if (param.DbType != null)
+                    if (dbType != null)
                     {
-                    p.DbType = param.DbType.Value;
+                        p.DbType = dbType.Value;
                     }
                     if (add)
                     {
@@ -2608,6 +2623,8 @@ protected void AddParameters(IDbCommand command, SqlMapper.Identity identity)
                     }
                     param.AttachedParam = p;
                 }
+                
+            }
         }
 
         /// <summary>

Tests/Program.cs

@@ -122,7 +122,12 @@ private static void RunTests()
                 {
                     method.Invoke(tester, null);
                     Console.WriteLine(" - OK!");
-                } catch (Exception ex)
+                } catch(TargetInvocationException tie)
+                {
+                    fail++;
+                    Console.WriteLine(" - " + tie.InnerException.Message);
+                    
+                }catch (Exception ex)
                 {
                     fail++;
                     Console.WriteLine(" - " + ex.Message);

Tests/Tests.cs

@@ -1598,6 +1598,34 @@ public void TestAppendingAList()
             result[2].IsEqualTo(3);
         }
 
+        public void TestAppendingAListAsDictionary()
+        {
+            DynamicParameters p = new DynamicParameters();
+            var list = new int[] { 1, 2, 3 };
+            var args = new Dictionary<string, object>();
+            args.Add("ids", list);
+            p.AddDynamicParams(args);
+
+            var result = connection.Query<int>("select * from (select 1 A union all select 2 union all select 3) X where A in @ids", p).ToList();
+
+            result[0].IsEqualTo(1);
+            result[1].IsEqualTo(2);
+            result[2].IsEqualTo(3);
+        }
+
+        public void TestAppendingAListByName()
+        {
+            DynamicParameters p = new DynamicParameters();
+            var list = new int[] { 1, 2, 3 };
+            p.Add("ids", list);
+
+            var result = connection.Query<int>("select * from (select 1 A union all select 2 union all select 3) X where A in @ids", p).ToList();
+
+            result[0].IsEqualTo(1);
+            result[1].IsEqualTo(2);
+            result[2].IsEqualTo(3);
+        }
+
         public void TestUniqueIdentifier()
         {
             var guid = Guid.NewGuid();