Add 'public new' convenience methods. Fixes #313

Author: bgrainger

src/MySqlConnector/MySqlClient/MySqlCommand.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Data;
 using System.Data.Common;
 using System.Threading;
@@ -34,8 +34,8 @@ public MySqlCommand(string commandText, MySqlConnection connection, MySqlTransac
 		{
 			CommandId = Interlocked.Increment(ref s_commandId);
 			CommandText = commandText;
-			DbConnection = connection;
-			DbTransaction = transaction;
+			Connection = connection;
+			Transaction = transaction;
 			m_parameterCollection = new MySqlParameterCollection();
 			CommandType = CommandType.Text;
 		}
@@ -49,6 +49,8 @@ public MySqlCommand(string commandText, MySqlConnection connection, MySqlTransac
 			}
 		}
 
+		public new MySqlParameter CreateParameter() => (MySqlParameter) base.CreateParameter();
+
 		public override void Cancel() => Connection.Cancel(this);
 
 		public override int ExecuteNonQuery() =>
@@ -57,6 +59,10 @@ public override int ExecuteNonQuery() =>
 		public override object ExecuteScalar() =>
 			ExecuteScalarAsync(IOBehavior.Synchronous, CancellationToken.None).GetAwaiter().GetResult();
 
+		public new MySqlDataReader ExecuteReader() => (MySqlDataReader) base.ExecuteReader();
+
+		public new MySqlDataReader ExecuteReader(CommandBehavior commandBehavior) => (MySqlDataReader) base.ExecuteReader(commandBehavior);
+
 		public override void Prepare()
 		{
 			// NOTE: Prepared statements in MySQL are not currently supported.
@@ -67,6 +73,8 @@ public override void Prepare()
 
 		public override string CommandText { get; set; }
 		public override int CommandTimeout { get; set; }
+		public new MySqlConnection Connection { get; set; }
+		public new MySqlTransaction Transaction { get; set; }
 
 		public override CommandType CommandType
 		{
@@ -99,9 +107,19 @@ public override UpdateRowSource UpdatedRowSource
 
 		public long LastInsertedId { get; internal set; }
 
-		protected override DbConnection DbConnection { get; set; }
+		protected override DbConnection DbConnection
+		{
+			get => Connection;
+			set => Connection = (MySqlConnection) value;
+		}
+
 		protected override DbParameterCollection DbParameterCollection => m_parameterCollection;
-		protected override DbTransaction DbTransaction { get; set; }
+
+		protected override DbTransaction DbTransaction
+		{
+			get => Transaction;
+			set => Transaction = (MySqlTransaction) value;
+		}
 
 		protected override DbParameter CreateDbParameter()
 		{
@@ -148,8 +166,6 @@ protected override void Dispose(bool disposing)
 			}
 		}
 
-		internal new MySqlConnection Connection => (MySqlConnection) DbConnection;
-
 		/// <summary>
 		/// Registers <see cref="Cancel"/> as a callback with <paramref name="token"/> if cancellation is supported.
 		/// </summary>
@@ -180,11 +196,11 @@ private bool IsValid(out Exception exception)
 			exception = null;
 			if (m_parameterCollection == null)
 				exception = new ObjectDisposedException(GetType().Name);
-			else if (DbConnection == null)
+			else if (Connection == null)
 				exception = new InvalidOperationException("Connection property must be non-null.");
-			else if (DbConnection.State != ConnectionState.Open && DbConnection.State != ConnectionState.Connecting)
-				exception = new InvalidOperationException("Connection must be Open; current state is {0}".FormatInvariant(DbConnection.State));
-			else if (DbTransaction != Connection.CurrentTransaction)
+			else if (Connection.State != ConnectionState.Open && Connection.State != ConnectionState.Connecting)
+				exception = new InvalidOperationException("Connection must be Open; current state is {0}".FormatInvariant(Connection.State));
+			else if (Transaction != Connection.CurrentTransaction)
 				exception = new InvalidOperationException("The transaction associated with this command is not the connection's active transaction.");
 			else if (string.IsNullOrWhiteSpace(CommandText))
 				exception = new InvalidOperationException("CommandText must be specified");

src/MySqlConnector/MySqlClient/MySqlConnection.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
@@ -22,6 +22,8 @@ public MySqlConnection()
 
 		public new MySqlTransaction BeginTransaction() => (MySqlTransaction) base.BeginTransaction();
 
+		public new MySqlTransaction BeginTransaction(IsolationLevel isolationLevel) => (MySqlTransaction) base.BeginTransaction(isolationLevel);
+
 		public Task<MySqlTransaction> BeginTransactionAsync(CancellationToken cancellationToken = default(CancellationToken)) =>
 			BeginDbTransactionAsync(IsolationLevel.Unspecified, AsyncIOBehavior, cancellationToken);
 
@@ -129,6 +131,8 @@ private async Task ChangeDatabaseAsync(IOBehavior ioBehavior, string databaseNam
 			m_session.DatabaseOverride = databaseName;
 		}
 
+		public new MySqlCommand CreateCommand() => (MySqlCommand) base.CreateCommand();
+
 		public override void Open() => OpenAsync(IOBehavior.Synchronous, CancellationToken.None).GetAwaiter().GetResult();
 
 		public override Task OpenAsync(CancellationToken cancellationToken) =>

src/MySqlConnector/MySqlClient/MySqlParameterCollection.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Data;
@@ -142,6 +142,12 @@ protected override void SetParameter(int index, DbParameter value)
 			set => SetParameter(index, value);
 		}
 
+		public new MySqlParameter this[string name]
+		{
+			get => (MySqlParameter) GetParameter(name);
+			set => SetParameter(name, value);
+		}
+
 		private void AddParameter(MySqlParameter parameter)
 		{
 			m_parameters.Add(parameter);

tests/SideBySide/QueryTests.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Data;
 using System.Linq;
@@ -763,6 +763,38 @@ public void Int64EnumParameter()
 			}
 		}
 
+		[Fact]
+		public void ReturnDerivedTypes()
+		{
+			using (MySqlTransaction transaction = m_database.Connection.BeginTransaction())
+			using (MySqlCommand command = m_database.Connection.CreateCommand())
+			{
+				command.CommandText = "select @param + @param2";
+
+				MySqlParameter parameter = command.CreateParameter();
+				parameter.ParameterName = "param";
+				parameter.Value = 1;
+				MySqlParameterCollection parameterCollection = command.Parameters;
+				parameterCollection.Add(parameter);
+
+				MySqlParameter parameter2 = parameterCollection.AddWithValue("param2", 2);
+
+				MySqlParameter parameterB = parameterCollection[0];
+				Assert.Same(parameter, parameterB);
+				MySqlParameter parameter2B = parameterCollection["param2"];
+				Assert.Same(parameter2, parameter2B);
+
+				using (MySqlDataReader reader = command.ExecuteReader())
+				{
+					Assert.True(reader.Read());
+					Assert.Equal(3L, reader.GetValue(0));
+					Assert.False(reader.Read());
+				}
+
+				transaction.Rollback();
+			}
+		}
+
 		class BoolTest
 		{
 			public int Id { get; set; }