VB.NET如果引发异常，是否会在Try / Catch中自动关闭SqlConnection？

Question

找不到确切的问题/答案。在VB.NET中，如果我在Try / Catch块中打开SqlConnection，并且抛出了异常（正确捕获），该连接是否隐式关闭，还是必须将其关闭？（如果尝试失败，它甚至会打开吗？）

我自己会“测试”，但是当抛出异常时，我真的不知道如何判断连接是打开还是关闭。

谢谢！

Answer 1

不。这就是为什么要在try / catch之前声明连接变量，并在其中添加finally，以确保可以放置和关闭连接的原因：

 Dim con As New SqlClientConnection( . . .)

 Try
      ' DB Operations (create, read, update, delete) here
      con.open()

 Catch SqlClientException (ex)

     ' Deal with exception
 Finally
      ' Code here will always run, whether or not the try code succeeded
      ' or if you wound up in a catch block. You can safely call .close()
      ' or (as shown below) .dispose() because if the connection is already
      ' closed/disposed, the call doesn't do anything.


      ' Dispose is what you want - it will not only close the
      ' connection, but it will release the .NET reference to
      ' the remote resource, freeing up that resource (the database
      ' in this case) to serve other clients.

      con.Dispose()

 End Try