Added support for a multi mapping grid reader

Dapper/SqlMapper.cs

@@ -214,6 +214,12 @@ internal Identity ForGrid(Type primaryType, int gridIndex)
             {
                 return new Identity(sql, connectionString, primaryType, parametersType, null, gridIndex);
             }
+
+            internal Identity ForGrid(Type primaryType, Type[] otherTypes, int gridIndex)
+            {
+                return new Identity(sql, connectionString, primaryType, parametersType, otherTypes, gridIndex);
+            }
+
             internal Identity(string sql, IDbConnection connection, Type type, Type parametersType, Type[] otherTypes)
                 : this(sql, connection.ConnectionString, type, parametersType, otherTypes, 0)
             { }
@@ -473,19 +479,27 @@ class DontMap { }
         static IEnumerable<TReturn> MultiMap<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(
             this IDbConnection cnn, string sql, object map, object param, IDbTransaction transaction, bool buffered, string splitOn, int? commandTimeout, CommandType? commandType)
         {
-            var results = MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(cnn, sql, map, param, transaction, splitOn, commandTimeout, commandType);
+            var results = MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(cnn, sql, map, param, transaction, splitOn, commandTimeout, commandType, null, null);
             return buffered ? results.ToList() : results;
         }
 
-        static IEnumerable<TReturn> MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(this IDbConnection cnn, string sql, object map, object param, IDbTransaction transaction, string splitOn, int? commandTimeout, CommandType? commandType)
+        static IEnumerable<TReturn> MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(this IDbConnection cnn, string sql, object map, object param, IDbTransaction transaction, string splitOn, int? commandTimeout, CommandType? commandType, IDataReader reader, Identity identity)
         {
-            Identity identity = new Identity(sql, cnn, typeof(TFirst), (object)param == null ? null : ((object)param).GetType(), new[] { typeof(TFirst), typeof(TSecond), typeof(TThird), typeof(TFourth), typeof(TFifth) });
+            identity = identity ?? new Identity(sql, cnn, typeof(TFirst), (object)param == null ? null : ((object)param).GetType(), new[] { typeof(TFirst), typeof(TSecond), typeof(TThird), typeof(TFourth), typeof(TFifth) });
             CacheInfo info = GetCacheInfo(identity);
 
-            using (var cmd = SetupCommand(cnn, transaction, sql, info.ParamReader, (object)param, commandTimeout, commandType))
+            IDbCommand ownedCommand = null;
+            IDataReader ownedReader = null;
+
+            try
             {
-                using (var reader = cmd.ExecuteReader())
+                if (reader == null)
                 {
+                    ownedCommand = SetupCommand(cnn, transaction, sql, info.ParamReader, (object)param, commandTimeout, commandType);
+                    ownedReader = ownedCommand.ExecuteReader();
+                    reader = ownedReader;
+                }
+
                 if (info.Deserializer == null)
                 {
                     int current = 0;
@@ -605,6 +619,22 @@ class DontMap { }
                     }
                 }
             }
+            finally
+            {
+                try
+                {
+                    if (ownedReader != null)
+                    {
+                        ownedReader.Dispose();
+                    }
+                }
+                finally
+                {
+                    if (ownedCommand != null)
+                    {
+                        ownedCommand.Dispose();
+                    }
+                }
             }
         }
 
@@ -1254,6 +1284,7 @@ public class GridReader : IDisposable
             private IDataReader reader;
             private IDbCommand command;
             private Identity identity;
+            
             internal GridReader(IDbCommand command, IDataReader reader, Identity identity)
             {
                 this.command = command;
@@ -1279,7 +1310,63 @@ public IEnumerable<T> Read<T>()
                 return ReadDeferred(gridIndex, deserializer, typedIdentity);
             }
 
-            // todo multimapping. 
+            private IEnumerable<TReturn> MultiReadInternal<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(object func, string splitOn)
+            {
+
+                var identity = this.identity.ForGrid(typeof(TReturn), new Type[] { 
+                    typeof(TFirst), 
+                    typeof(TSecond),
+                    typeof(TThird),
+                    typeof(TFourth),
+                    typeof(TFifth)
+                }, gridIndex);
+                try
+                {
+                    foreach (var r in SqlMapper.MultiMapImpl<TFirst, TSecond, DontMap, DontMap, DontMap, TReturn>(null, null, func, null, null, splitOn, null, null, reader, identity))
+                    {
+                        yield return r;
+                    }
+                }
+                finally
+                {
+                    NextResult();
+                }
+            }
+
+#if CSHARP30  
+            public IEnumerable<TReturn> Read<TFirst, TSecond, TReturn>(Func<TFirst, TSecond, TReturn> func, string splitOn)
+#else
+            public IEnumerable<TReturn> Read<TFirst, TSecond, TReturn>(Func<TFirst, TSecond, TReturn> func, string splitOn = "id")
+#endif
+            {
+                return MultiReadInternal<TFirst, TSecond, DontMap, DontMap, DontMap, TReturn>(func, splitOn);
+            }
+
+#if CSHARP30  
+            public IEnumerable<TReturn> Read<TFirst, TSecond, TThird, TReturn>(Func<TFirst, TSecond, TThird, TReturn> func, string splitOn)
+#else
+            public IEnumerable<TReturn> Read<TFirst, TSecond, TThird, TReturn>(Func<TFirst, TSecond, TThird, TReturn> func, string splitOn = "id")
+#endif
+            {
+                return MultiReadInternal<TFirst, TSecond, TThird, DontMap, DontMap, TReturn>(func, splitOn);
+            }
+
+#if CSHARP30  
+            public IEnumerable<TReturn> Read<TFirst, TSecond, TThird, TFourth, TReturn>(Func<TFirst, TSecond, TThird, TFourth, TReturn> func, string splitOn)
+#else
+            public IEnumerable<TReturn> Read<TFirst, TSecond, TThird, TFourth, TReturn>(Func<TFirst, TSecond, TThird, TFourth, TReturn> func, string splitOn = "id")
+#endif
+            {
+                return MultiReadInternal<TFirst, TSecond, TThird, TFourth, DontMap, TReturn>(func, splitOn);
+            }
+
+#if !CSHARP30  
+            public IEnumerable<TReturn> Read<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(Func<TFirst, TSecond, TThird, TFourth, TFifth, TReturn> func, string splitOn = "id")
+
+            {
+                return MultiReadInternal<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(func, splitOn);
+            }
+#endif
 
             private IEnumerable<T> ReadDeferred<T>(int index, Func<IDataReader, T> deserializer, Identity typedIdentity)
             {

Tests/Tests.cs

@@ -348,6 +348,51 @@ public void TestMultiMap()
         }
 
 
+
+        public void TestMultiMapGridReader()
+        {
+            var createSql = @"
+                create table #Users (Id int, Name varchar(20))
+                create table #Posts (Id int, OwnerId int, Content varchar(20))
+
+                insert #Users values(99, 'Sam')
+                insert #Users values(2, 'I am')
+
+                insert #Posts values(1, 99, 'Sams Post1')
+                insert #Posts values(2, 99, 'Sams Post2')
+                insert #Posts values(3, null, 'no ones post')
+";
+            connection.Execute(createSql);
+
+            var sql =
+@"select p.*, u.Id, u.Name + '0' Name from #Posts p 
+left join #Users u on u.Id = p.OwnerId 
+Order by p.Id
+
+select p.*, u.Id, u.Name + '1' Name from #Posts p 
+left join #Users u on u.Id = p.OwnerId 
+Order by p.Id
+";
+
+            var grid = connection.QueryMultiple(sql);
+
+            for (int i = 0; i < 2; i++)
+            {
+                var data = grid.Read<Post, User, Post>((post, user) => { post.Owner = user; return post; }).ToList();
+                var p = data.First();
+
+                p.Content.IsEqualTo("Sams Post1");
+                p.Id.IsEqualTo(1);
+                p.Owner.Name.IsEqualTo("Sam" + i);
+                p.Owner.Id.IsEqualTo(99);
+
+                data[2].Owner.IsNull();
+            }
+            
+            connection.Execute("drop table #Users drop table #Posts");
+
+        }
+
         public void TestMultiMapDynamic()
         {
             var createSql = @"
@@ -810,6 +855,7 @@ public void ParentChildIdentityAssociations()
             parents[3].Children.Select(c => c.Id).SequenceEqual(new[] { 5 }).IsTrue();
         }
 
+
         /* TODO:
          * 
         public void TestMagicParam()