Rationalize FireOutputCallbacks, and apply to remaining methods

Dapper NET40/SqlMapper.cs

@@ -52,8 +52,19 @@ public enum CommandFlags
     /// <summary>
     /// Represents the key aspects of a sql operation
     /// </summary>
-    public  struct CommandDefinition
+    public struct CommandDefinition
     {
+        internal static CommandDefinition ForCallback(object parameters)
+        {
+            if(parameters is DynamicParameters)
+            {
+                return new CommandDefinition(parameters);
+            }
+            else
+            {
+                return default(CommandDefinition);
+            }
+        }
         private readonly string commandText;
         private readonly object parameters;
         private readonly IDbTransaction transaction;
@@ -62,7 +73,13 @@ public  struct CommandDefinition
         private readonly CommandFlags flags;
 
 
-
+        internal void FireOutputCallbacks()
+        {
+            if (parameters is DynamicParameters)
+            {
+                ((DynamicParameters)parameters).FireOutputCallbacks();
+            }
+        }
         /// <summary>
         /// The command (sql or a stored-procedure name) to execute
         /// </summary>
@@ -130,6 +147,11 @@ public  struct CommandDefinition
 #endif
         }
 
+        private CommandDefinition(object parameters) : this()
+        {
+            this.parameters = parameters;
+        }
+
 #if ASYNC
         private readonly CancellationToken cancellationToken;
         /// <summary>
@@ -1120,7 +1142,7 @@ public static GridReader QueryMultiple(this IDbConnection cnn, string sql, objec
 #if CSHARP30
 this IDbConnection cnn, string sql, object param, IDbTransaction transaction, int? commandTimeout, CommandType? commandType
 #else
-this IDbConnection cnn, string sql, dynamic param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
+this IDbConnection cnn, string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1145,7 +1167,7 @@ public static int Execute(this IDbConnection cnn, CommandDefinition command)
 #if CSHARP30
 this IDbConnection cnn, string sql, object param, IDbTransaction transaction, int? commandTimeout, CommandType? commandType
 #else
-this IDbConnection cnn, string sql, dynamic param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
+this IDbConnection cnn, string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1161,7 +1183,7 @@ public static int Execute(this IDbConnection cnn, CommandDefinition command)
 #if CSHARP30
 this IDbConnection cnn, string sql, object param, IDbTransaction transaction, int? commandTimeout, CommandType? commandType
 #else
-this IDbConnection cnn, string sql, dynamic param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
+this IDbConnection cnn, string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1229,6 +1251,7 @@ private static int ExecuteImpl(this IDbConnection cnn, ref CommandDefinition com
                             total += cmd.ExecuteNonQuery();
                         }
                     }
+                    command.FireOutputCallbacks();
                 } finally
                 {
                     if (wasClosed) cnn.Close();
@@ -1268,7 +1291,7 @@ private static int ExecuteImpl(this IDbConnection cnn, ref CommandDefinition com
 #if CSHARP30
 this IDbConnection cnn, string sql, object param, IDbTransaction transaction, int? commandTimeout, CommandType? commandType
 #else
-this IDbConnection cnn, string sql, dynamic param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
+this IDbConnection cnn, string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1305,7 +1328,7 @@ public static IDataReader ExecuteReader(this IDbConnection cnn, CommandDefinitio
         /// <summary>
         /// Return a list of dynamic objects, reader is closed after the call
         /// </summary>
-        public static IEnumerable<dynamic> Query(this IDbConnection cnn, string sql, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null)
+        public static IEnumerable<dynamic> Query(this IDbConnection cnn, string sql, object param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null)
         {
             return Query<DapperRow>(cnn, sql, param as object, transaction, buffered, commandTimeout, commandType);
         }
@@ -1362,7 +1385,7 @@ public static IEnumerable<dynamic> Query(this IDbConnection cnn, string sql, dyn
 #if CSHARP30
 this IDbConnection cnn, string sql, object param, IDbTransaction transaction, bool buffered, int? commandTimeout, CommandType? commandType
 #else
-this IDbConnection cnn, string sql, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null
+this IDbConnection cnn, string sql, object param = null, IDbTransaction transaction = null, bool buffered = true, int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1412,7 +1435,7 @@ public static IEnumerable<T> Query<T>(this IDbConnection cnn, CommandDefinition
 #if CSHARP30
 this IDbConnection cnn, string sql, object param, IDbTransaction transaction, int? commandTimeout, CommandType? commandType
 #else
-            this IDbConnection cnn, string sql, dynamic param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
+            this IDbConnection cnn, string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1441,7 +1464,7 @@ private static GridReader QueryMultipleImpl(this IDbConnection cnn, ref CommandD
                 cmd = command.SetupCommand(cnn, info.ParamReader);
                 reader = cmd.ExecuteReader(wasClosed ? CommandBehavior.CloseConnection | CommandBehavior.SequentialAccess : CommandBehavior.SequentialAccess);
 
-                var result = new GridReader(cmd, reader, identity);
+                var result = new GridReader(cmd, reader, identity, command.Parameters as DynamicParameters);
                 wasClosed = false; // *if* the connection was closed and we got this far, then we now have a reader
                 // with the CloseConnection flag, so the reader will deal with the connection; we
                 // still need something in the "finally" to ensure that broken SQL still results
@@ -1503,10 +1526,13 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
                         yield return (T)Convert.ChangeType(val, convertToType, CultureInfo.InvariantCulture);
                     }
                 }
+                while (reader.NextResult()) { }
                 // happy path; close the reader cleanly - no
                 // need for "Cancel" etc
                 reader.Dispose();
                 reader = null;
+
+                command.FireOutputCallbacks();
             }
             finally
             {
@@ -1541,7 +1567,7 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
 #if CSHARP30
 this IDbConnection cnn, string sql, Func<TFirst, TSecond, TReturn> map, object param, IDbTransaction transaction, bool buffered, string splitOn, int? commandTimeout, CommandType? commandType
 #else
-this IDbConnection cnn, string sql, Func<TFirst, TSecond, TReturn> map, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
+this IDbConnection cnn, string sql, Func<TFirst, TSecond, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1569,7 +1595,7 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
 #if CSHARP30
 this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TReturn> map, object param, IDbTransaction transaction, bool buffered, string splitOn, int? commandTimeout, CommandType? commandType
 #else
-this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TReturn> map, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
+this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1598,7 +1624,7 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
 #if CSHARP30
 this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TReturn> map, object param, IDbTransaction transaction, bool buffered, string splitOn, int? commandTimeout, CommandType? commandType
 #else
-this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TReturn> map, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
+this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
 #endif
 )
         {
@@ -1626,7 +1652,7 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
         /// <param name="commandType"></param>
         /// <returns></returns>
         public static IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(
-            this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TReturn> map, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
+            this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
 )
         {
             return MultiMap<TFirst, TSecond, TThird, TFourth, TFifth, DontMap, DontMap, TReturn>(cnn, sql, map, param as object, transaction, buffered, splitOn, commandTimeout, commandType);
@@ -1653,7 +1679,7 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
         /// <param name="commandType"></param>
         /// <returns></returns>
         public static IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TReturn>(
-            this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TReturn> map, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
+            this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null
 )
         {
             return MultiMap<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, DontMap, TReturn>(cnn, sql, map, param as object, transaction, buffered, splitOn, commandTimeout, commandType);
@@ -1681,7 +1707,7 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
         /// <param name="commandTimeout"></param>
         /// <param name="commandType"></param>
         /// <returns></returns>
-        public static IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn> map, dynamic param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
+        public static IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(this IDbConnection cnn, string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
         {
             return MultiMap<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(cnn, sql, map, param as object, transaction, buffered, splitOn, commandTimeout, commandType);
         }
@@ -1734,6 +1760,7 @@ partial class DontMap { }
                     {
                         yield return mapIt(reader);
                     }
+                    command.FireOutputCallbacks();
                 }
             }
             finally
@@ -3022,17 +3049,14 @@ private static int ExecuteCommand(IDbConnection cnn, ref CommandDefinition comma
             {
                 cmd = command.SetupCommand(cnn, paramReader);
                 if (wasClosed) cnn.Open();
-                return cmd.ExecuteNonQuery();
+                int result = cmd.ExecuteNonQuery();
+                command.FireOutputCallbacks();
+                return result;
             }
             finally
             {
                 if (wasClosed) cnn.Close();
                 if (cmd != null) cmd.Dispose();
-
-                if (command.Parameters is DynamicParameters)
-                {
-                    ((DynamicParameters)command.Parameters).FireOutputCallbacks();
-                }
             }
         }
 
@@ -3054,16 +3078,12 @@ private static T ExecuteScalarImpl<T>(IDbConnection cnn, ref CommandDefinition c
                 cmd = command.SetupCommand(cnn, paramReader);
                 if (wasClosed) cnn.Open();
                 result =cmd.ExecuteScalar();
+                command.FireOutputCallbacks();
             }
             finally
             {
                 if (wasClosed) cnn.Close();
                 if (cmd != null) cmd.Dispose();
-
-                if (command.Parameters is DynamicParameters)
-                {
-                    ((DynamicParameters)command.Parameters).FireOutputCallbacks();
-                }
             }
             return Parse<T>(result);
         }
@@ -3081,17 +3101,14 @@ private static IDataReader ExecuteReaderImpl(IDbConnection cnn, ref CommandDefin
                 if (wasClosed) commandBehavior |= CommandBehavior.CloseConnection;
                 var reader = cmd.ExecuteReader(commandBehavior);
                 wasClosed = false; // don't dispose before giving it to them!
+
+                // note: command.FireOutputCallbacks(); would be useless here; parameters come at the **end** of the TDS stream
                 return reader;
             }
             finally
             {
                 if (wasClosed) cnn.Close();
                 if (cmd != null) cmd.Dispose();
-
-                if (command.Parameters is DynamicParameters)
-                {
-                    ((DynamicParameters)command.Parameters).FireOutputCallbacks();
-                }
             }
         }
 
@@ -3785,11 +3802,12 @@ public partial class GridReader : IDisposable
             private IDbCommand command;
             private Identity identity;
 
-            internal GridReader(IDbCommand command, IDataReader reader, Identity identity)
+            internal GridReader(IDbCommand command, IDataReader reader, Identity identity, DynamicParameters dynamicParams)
             {
                 this.command = command;
                 this.reader = reader;
                 this.identity = identity;
+                this.dynamicParams = dynamicParams;
             }
 
 #if !CSHARP30
@@ -3996,6 +4014,8 @@ private IEnumerable<T> ReadDeferred<T>(int index, Func<IDataReader, object> dese
             }
             private int gridIndex, readCount;
             private bool consumed;
+            private DynamicParameters dynamicParams;
+
             /// <summary>
             /// Has the underlying reader been consumed?
             /// </summary>
@@ -4020,7 +4040,7 @@ private void NextResult()
                     // need for "Cancel" etc
                     reader.Dispose();
                     reader = null;
-
+                    if (dynamicParams != null) dynamicParams.FireOutputCallbacks();
                     Dispose();
                 }
             }

Dapper NET45/SqlMapperAsync.cs

@@ -95,13 +95,15 @@ private static async Task<IEnumerable<T>> QueryAsync<T>(this IDbConnection cnn,
                         {
                             buffer.Add((T)func(reader));
                         }
+                        while (await reader.NextResultAsync().ConfigureAwait(false)) { }
+                        command.FireOutputCallbacks();
                         return buffer;
                     }
                     else
                     {
                         // can't use ReadAsync / cancellation; but this will have to do
                         wasClosed = false; // don't close if handing back an open reader; rely on the command-behavior
-                        var deferred = ExecuteReaderSync<T>(reader, func);
+                        var deferred = ExecuteReaderSync<T>(reader, func, command.Parameters);
                         reader = null; // to prevent it being disposed before the caller gets to see it
                         return deferred;
                     }
@@ -211,7 +213,6 @@ private static async Task<int> ExecuteMultiImplAsync(IDbConnection cnn, CommandD
                             using (pending.Dequeue().Command) { } // dispose commands
                         }
                     }
-                    return total;
                 }
                 else
                 {
@@ -236,6 +237,8 @@ private static async Task<int> ExecuteMultiImplAsync(IDbConnection cnn, CommandD
                         }
                     }
                 }
+
+                command.FireOutputCallbacks();
             }
             finally
             {
@@ -253,7 +256,9 @@ private static async Task<int> ExecuteImplAsync(IDbConnection cnn, CommandDefini
                 try
                 {
                     if (wasClosed) await ((DbConnection)cnn).OpenAsync(command.CancellationToken).ConfigureAwait(false);
-                    return await cmd.ExecuteNonQueryAsync(command.CancellationToken).ConfigureAwait(false);
+                    var result = await cmd.ExecuteNonQueryAsync(command.CancellationToken).ConfigureAwait(false);
+                    command.FireOutputCallbacks();
+                    return result;
                 }
                 finally
                 {
@@ -446,7 +451,7 @@ private static async Task<int> ExecuteImplAsync(IDbConnection cnn, CommandDefini
                 using (var reader = await cmd.ExecuteReaderAsync(wasClosed ? CommandBehavior.CloseConnection | CommandBehavior.SequentialAccess : CommandBehavior.SequentialAccess, command.CancellationToken).ConfigureAwait(false))
                 {
                     if (!command.Buffered) wasClosed = false; // handing back open reader; rely on command-behavior
-                    var results = MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(null, default(CommandDefinition), map, splitOn, reader, identity);
+                    var results = MultiMapImpl<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(null, CommandDefinition.ForCallback(command.Parameters), map, splitOn, reader, identity);
                     return command.Buffered ? results.ToList() : results;
                 }
             } finally
@@ -455,12 +460,15 @@ private static async Task<int> ExecuteImplAsync(IDbConnection cnn, CommandDefini
             }
         }
 
-        private static IEnumerable<T> ExecuteReaderSync<T>(IDataReader reader, Func<IDataReader,object> func)
+        private static IEnumerable<T> ExecuteReaderSync<T>(IDataReader reader, Func<IDataReader,object> func, object parameters)
         {
             while (reader.Read())
             {
                 yield return (T)func(reader);
             }
+            while (reader.NextResult()) { }
+            if (parameters is DynamicParameters)
+                ((DynamicParameters)parameters).FireOutputCallbacks();
         }
 
         /// <summary>
@@ -481,7 +489,7 @@ private static IEnumerable<T> ExecuteReaderSync<T>(IDataReader reader, Func<IDat
         partial class GridReader
         {
             CancellationToken cancel;
-            internal GridReader(IDbCommand command, IDataReader reader, Identity identity, CancellationToken cancel) : this(command, reader, identity)
+            internal GridReader(IDbCommand command, IDataReader reader, Identity identity, DynamicParameters dynamicParams, CancellationToken cancel) : this(command, reader, identity, dynamicParams)
             {
                 this.cancel = cancel;
             }
@@ -524,7 +532,7 @@ private async Task NextResultAsync()
                     // need for "Cancel" etc
                     reader.Dispose();
                     reader = null;
-
+                    if (dynamicParams != null) dynamicParams.FireOutputCallbacks();
                     Dispose();
                 }
             }
@@ -600,7 +608,7 @@ public static async Task<GridReader> QueryMultipleAsync(this IDbConnection cnn,
                 cmd = (DbCommand)command.SetupCommand(cnn, info.ParamReader);
                 reader = await cmd.ExecuteReaderAsync(wasClosed ? CommandBehavior.CloseConnection | CommandBehavior.SequentialAccess : CommandBehavior.SequentialAccess, command.CancellationToken).ConfigureAwait(false);
 
-                var result = new GridReader(cmd, reader, identity, command.CancellationToken);
+                var result = new GridReader(cmd, reader, identity, command.Parameters as DynamicParameters, command.CancellationToken);
                 wasClosed = false; // *if* the connection was closed and we got this far, then we now have a reader
                 // with the CloseConnection flag, so the reader will deal with the connection; we
                 // still need something in the "finally" to ensure that broken SQL still results
@@ -758,6 +766,7 @@ private async static Task<T> ExecuteScalarImplAsync<T>(IDbConnection cnn, Comman
                 cmd = (DbCommand)command.SetupCommand(cnn, paramReader);
                 if (wasClosed) await ((DbConnection)cnn).OpenAsync(command.CancellationToken).ConfigureAwait(false);
                 result = await cmd.ExecuteScalarAsync(command.CancellationToken).ConfigureAwait(false);
+                command.FireOutputCallbacks();
             }
             finally
             {

DapperTests NET45/Tests.cs

@@ -355,5 +355,199 @@ public void Issue22_ExecuteScalar()
                 k.IsNull();
             }
         }
+
+        public void TestSupportForDynamicParametersOutputExpressions()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                connection.ExecuteAsync(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+SET @AddressPersonId = @PersonId", p).Wait();
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+            }
+        }
+        public void TestSupportForDynamicParametersOutputExpressions_Scalar()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                var result = (int)connection.ExecuteScalarAsync(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+SET @AddressPersonId = @PersonId
+select 42", p).Result;
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                result.IsEqualTo(42);
+            }
+        }
+        public void TestSupportForDynamicParametersOutputExpressions_Query_Default()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                var result = connection.QueryAsync<int>(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+SET @AddressPersonId = @PersonId
+select 42", p).Result.Single();
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                result.IsEqualTo(42);
+            }
+        }
+        public void TestSupportForDynamicParametersOutputExpressions_Query_Buffered()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                var result = connection.QueryAsync<int>(new CommandDefinition(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+SET @AddressPersonId = @PersonId
+select 42", p, flags: CommandFlags.Buffered)).Result.Single();
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                result.IsEqualTo(42);
+            }
+        }
+        public void TestSupportForDynamicParametersOutputExpressions_Query_NonBuffered()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                var result = connection.QueryAsync<int>(new CommandDefinition(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+SET @AddressPersonId = @PersonId
+select 42", p, flags: CommandFlags.None)).Result.Single();
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                result.IsEqualTo(42);
+            }
+        }
+        public void TestSupportForDynamicParametersOutputExpressions_QueryMultiple()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                int x, y;
+                using(var multi = connection.QueryMultipleAsync(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+select 42
+select 17
+SET @AddressPersonId = @PersonId", p).Result)
+                {
+                    x = multi.ReadAsync<int>().Result.Single();
+                    y = multi.ReadAsync<int>().Result.Single();
+                }
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                x.IsEqualTo(42);
+                y.IsEqualTo(17);
+            }
+        }
+        class Person
+        {
+            public int PersonId { get; set; }
+            public string Name { get; set; }
+            public string Occupation { get; private set; }
+            public int NumberOfLegs = 2;
+            public Address Address { get; set; }
+        }
+        class Address
+        {
+            public int AddressId { get; set; }
+            public string Name { get; set; }
+            public int PersonId { get; set; }
+        }
     }
 }
\ No newline at end of file

Tests/Tests.cs

@@ -1201,7 +1201,130 @@ public void TestSupportForDynamicParametersOutputExpressions()
             bob.Address.Name.IsEqualTo("bobs burgers");
             bob.Address.PersonId.IsEqualTo(2);
         }
+        public void TestSupportForDynamicParametersOutputExpressions_Scalar()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                var result = (int)connection.ExecuteScalar(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+SET @AddressPersonId = @PersonId
+select 42", p);
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                result.IsEqualTo(42);
+            }
+        }
+        public void TestSupportForDynamicParametersOutputExpressions_Query_Buffered()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                var result = connection.Query<int>(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+SET @AddressPersonId = @PersonId
+select 42", p, buffered: true).Single();
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                result.IsEqualTo(42);
+            }
+        }
+        public void TestSupportForDynamicParametersOutputExpressions_Query_NonBuffered()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                var result = connection.Query<int>(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+SET @AddressPersonId = @PersonId
+select 42", p, buffered: false).Single();
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                result.IsEqualTo(42);
+            }
+        }
 
+        public void TestSupportForDynamicParametersOutputExpressions_QueryMultiple()
+        {
+            using (var connection = Program.GetOpenConnection())
+            {
+                var bob = new Person { Name = "bob", PersonId = 1, Address = new Address { PersonId = 2 } };
+
+                var p = new DynamicParameters(bob);
+                p.Output(bob, b => b.PersonId);
+                p.Output(bob, b => b.Occupation);
+                p.Output(bob, b => b.NumberOfLegs);
+                p.Output(bob, b => b.Address.Name);
+                p.Output(bob, b => b.Address.PersonId);
+
+                int x, y;
+                using (var multi = connection.QueryMultiple(@"
+SET @Occupation = 'grillmaster' 
+SET @PersonId = @PersonId + 1 
+SET @NumberOfLegs = @NumberOfLegs - 1
+SET @AddressName = 'bobs burgers'
+select 42
+select 17
+SET @AddressPersonId = @PersonId", p))
+                {
+                    x = multi.Read<int>().Single();
+                    y = multi.Read<int>().Single();
+                }
+
+                bob.Occupation.IsEqualTo("grillmaster");
+                bob.PersonId.IsEqualTo(2);
+                bob.NumberOfLegs.IsEqualTo(1);
+                bob.Address.Name.IsEqualTo("bobs burgers");
+                bob.Address.PersonId.IsEqualTo(2);
+                x.IsEqualTo(42);
+                y.IsEqualTo(17);
+            }
+        }
         public void TestSupportForExpandoObjectParameters()
         {
             dynamic p = new ExpandoObject();