当我将鼠标悬停在Sub
我是 lambda 表达式的新手。任何帮助表示赞赏。我正在使用 VS 2010 和 .NET 3.5。
Sub Main()
ExecuteWithinTransaction(Sub(con, trans) InsertA("Al", con, trans))
ExecuteWithinTransaction(Sub(con, trans) InsertB("Bert", con, trans))
ExecuteWithinTransaction(Sub(con, trans)
InsertA("Albert", con, trans)
InsertB("Einstein", con, trans)
End Sub)
End Sub
''' <summary>
''' Executes an action within a transaction. handles connection and transaction management
''' </summary>
''' <param name="action">The action to be executed</param>
Sub ExecuteWithinTransaction(ByVal action As Action(Of SqlConnection, SqlTransaction))
Dim connection As SqlConnection = New SqlConnection("CONNECTIONSTRING")
connection.Open()
Try
Dim transaction = connection.BeginTransaction()
Try
action(connection, transaction)
transaction.Commit()
Catch ex As Exception
transaction.Rollback()
Throw 'rethrow exception preserving original stacktrace
End Try
Finally
connection.Close()
End Try
End Sub
Sub InsertA(ByVal name As String, ByVal connection As SqlConnection, ByVal transaction As SqlTransaction)
Dim cmd As SqlCommand = New SqlCommand("INSERT INTO XXX (Name) VALUES (@NAME)", connection, transaction)
cmd.Parameters.AddWithValue("@Name", name)
cmd.ExecuteNonQuery()
End Sub
Sub InsertB(ByVal name As String, ByVal connection As SqlConnection, ByVal transaction As SqlTransaction)
Dim cmd As SqlCommand = New SqlCommand("INSERT INTO YYY (Name) VALUES (@NAME)", connection, transaction)
cmd.Parameters.AddWithValue("@Name", name)
cmd.ExecuteNonQuery()
End Sub