.net - .Net TCP客户端通信问题

我对网络编程不熟悉，正在尝试在ICE API测试服务器和我的应用程序之间建立通信。当我试图登录到服务器时，下面的代码只工作一次。换句话说，当我发送我的登录消息时，服务器会用成功的登录回复我。一旦我得到这个消息，我就向服务器发送下一条消息，但作为答复，我得到的是0，这意味着服务器已经断开了连接。有人能看看我的客户逻辑，并给我指出正确的方向，为什么会发生上述情况。请帮我解决这个问题，因为我已经没有结果了。谢谢您。

Public Function connect() As Boolean
            bConnected = True
            Dim port As Int32 = Convert.ToInt32("80")
            Dim server As String = "63.247.113.201"
            Try
                objClient = New System.Net.Sockets.TcpClient(server, port)
                objClient.NoDelay = False
                objClient.Client.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.KeepAlive, 1)
                objClient.GetStream.BeginRead(byReadBuffer, 0, BYTES_TO_READ, New AsyncCallback(AddressOf doRead), Nothing)
            Catch ex As Exception
                RaiseEvent exErr(ex.ToString)
                bConnected = False
            End Try

            Return bConnected
        End Function

Public Function DoTCPRequest(ByVal data As String, ByVal resetSession As Boolean) As String
            Dim objSw As IO.StreamWriter

            Try
                objSw = New IO.StreamWriter(objClient.GetStream)
                objSw.Write(data & vbCrLf)
                objSw.Flush()
                Console.WriteLine("Sent:" + data)
           Catch ex As Exception
                RaiseEvent exErr(ex.ToString)
            End Try

            objClient.GetStream.BeginRead(byReadBuffer, 0, BYTES_TO_READ, AddressOf Me.doRead, Nothing)
            Return System.Text.Encoding.UTF8.GetString(byReadBuffer, 0, BYTES_TO_READ)
        End Function

      Private Sub doRead(ByVal ar As System.IAsyncResult)
            Dim nTotalRead As Integer
            Try
                Try
                    nTotalRead = objClient.GetStream.EndRead(ar)                     Catch ex As Exception
                    RaiseEvent exErr(ex.ToString)
                End Try

                If nTotalRead > 0 Then
                    Dim szReceivedString As String = System.Text.Encoding.UTF8.GetString(byReadBuffer, 0, nTotalRead)
                    RaiseEvent dataReceived(szReceivedString)
                    Console.WriteLine("Recv1:" + szReceivedString)
                End If

               objClient.GetStream.BeginRead(byReadBuffer, 0, BYTES_TO_READ, New AsyncCallback(AddressOf doRead), Nothing)

            Catch ex As Exception
                RaiseEvent exErr(ex.ToString)
            End Try

        End Sub

最佳答案

@lberezka，我在代码中看到一个奇怪的东西。是否要在doread（）方法内查看以下代码行？

objClient.GetStream.BeginRead(byReadBuffer, 0, BYTES_TO_READ, New AsyncCallback(AddressOf doRead), Nothing) 'Begin the reading again.

理想情况下，在任何异步调用（begin-kind）中，回调句柄都应该接收应答并尝试使用end方法结束调用。在您的案例中，stream.endread。
我在代码中看到的是，您一次又一次递归地调用begin方法，但在任何地方都看不到endread。
它能给你任何线索吗？