VB.NET: TCP 客户端套接字超时？

Question

我有一个 TCP 客户端套接字，它在加载 Form1 时连接到服务器。如果连接时间太长，我需要一种方法让客户端套接字 "give up" 尝试连接到远程服务器。即 30 秒后超时。

目前，当套接字由于任何原因无法连接到服务器时，在可以访问服务器之前，表单似乎会冻结。

可能值得注意的是我正在使用 System.Net.Sockets.TcpClient()

这是用于创建连接的 My Sub：

Public serverStream As NetworkStream
Public clientSocket As New System.Net.Sockets.TcpClient()    

Public Sub CreateTCPConnection()
    Try
        clientSocket.Connect(System.Net.IPAddress.Parse(My.Settings.ServerIP), My.Settings.ServerPort)
        ConnectionStatusLbl.Text = "Connection: Connected"
        ConnectionStatusPB.Image = My.Resources.LED_Green
        'This should work according to MSDN but does not
        clientSocket.SendTimeout = 3000
        clientSocket.ReceiveTimeout = 3000
        UpdateTimer.Start()
    Catch ex As Exception
        ConnectionStatusLbl.Text = "Connection: Not Connected"
        ConnectionStatusPB.Image = My.Resources.LED_Red
        clientSocket.Close()
        MsgBox(ex.ToString)
    End Try


End Sub

Answer 1

您可以线程化整个 CreateTCPConnection 函数，然后在主线程中使用 Timer 在 X 秒后中止线程，如果 public 布尔值未设置为真.

线程初始化的伪代码：

Dim isConnected as Boolean


Private Sub Form1_Load( _
   ByVal sender As System.Object, ByVal e As System.EventArgs) _
   Handles MyBase.Load
   isConnected = false;
   trd = New Thread(AddressOf CreateTCPConnection)
   trd.IsBackground = True
   //Afer the start function the thread tries to connect asyncron to your server
   trd.Start()
   Timer timer = new Timer();
   //Start the timer to check the boolean
   myTimer.Tick += new EventHandler(TimerEventProcessor);
   myTimer.Start()

End Sub

Private Sub CreateTCPConnection()
 //Your Connection method
End Sub

//Checks the isConnected status each second. If isConnected is false and 3 seconds are reached, the thread gets aborted.
Private Sub TimerEventProcessor(Object myObject,
                                        EventArgs myEventArgs) 
   if(myEventArgs.elapsedTime >= 3 AND isConnected == false) Then
      trd.Abort();
   End if
End Sub

这是一个小的解决方法。

VB.NET: TCP 客户端套接字超时？

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