EndReceive 永远不会完成接收 vb Net

Question

我正在使用example of Microsoft（Visual Basic net 4.5）发送和接收数据抛出套接字，但这个块总是正确的：

    Private Sub OnRecieve(ByVal ar As IAsyncResult)
    Try
        Dim state As StateObject = CType(ar.AsyncState, StateObject)
        Dim client As Socket = state.workSocket

        ' Read data from the remote device.
        Dim bytesRead As Integer = client.EndReceive(ar)

        If bytesRead > 0 Then
            ' There might be more data, so store the data received so far.
            state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead))

            '  Se supone que vuelve por los datos que faltan, pero no lo hace (Creo)
            client.BeginReceive(state.buffer, 0, state.BufferSize, 0, AddressOf OnRecieve, state)

        Else
            ' All the data has arrived; put it in response.
            If state.sb.Length > 1 Then
                VariablesGlobales.response = state.sb.ToString()
            End If
            ' Signal that all bytes have been received.
            receiveDone.Set()
        End If


    Catch ex As Exception
        'clientSocket.Close()
        RaiseEvent FallaAlRecibirDatos(ex.Message, "Falla en endReive.")
    End Try

End Sub

但是我发送、发送、发送消息，无论是短消息还是大消息，它都不会进入 else 语句。在这里，我的初始代码：

Public Sub Conectar()

    clientSocket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)

    Dim ipEndPoint As IPEndPoint = New IPEndPoint(Me.ipAddress, VariablesGlobales.Puerto)
    clientSocket.BeginConnect(ipEndPoint, New AsyncCallback(AddressOf OnConnect), clientSocket)

    ' Wait for connect.
    connectDone.WaitOne()

    EnviarDatosPersonales()

    ' Wait for send datas.
    sendDone.WaitOne()

    While True
        AvtivarEscuchador()
        receiveDone.WaitOne()

        DescifrarMsg(VariablesGlobales.response)
    End While
End Sub

我确实收到了服务器发送的消息，我可以在 Visual Studio 中逐个步骤地看到它们，但我不知道为什么它永远不会进入 else，我的意思是，它永远不会完成接收数据。

我阅读了the answer of Marc Gravell，但我更喜欢如何解决这个问题的代码示例，我不知道该怎么做。

此外，我删除了“else”，它用许多白线填充了我的文本框，就像许多接收的无限循环。请帮我。谢谢。

抱歉，这里是 Escuchador 函数：

Private Sub AvtivarEscuchador()

    ' Borramos los datos de respuesta anterior
    VariablesGlobales.response = ""

    ' Activamos el escuchador
    Try
        ' Create the state object.
        Dim state As New StateObject()
        state.workSocket = Me.clientSocket

        ' Begin receiving the data from the remote device.
        Me.clientSocket.BeginReceive(state.buffer, 0, state.BufferSize, 0, AddressOf OnRecieve, state)
    Catch e As Exception
        RaiseEvent FallaAlRecibirDatos("No se pudo activar el escuchador.", "Falla al intentar escuchar.")
    End Try

End Sub

Answer 1

正如您已经链接到 Marc Gravell 的答案，他在重要的第一句话中的第一句话：

“如果流已关闭并且所有数据都已被消耗，EndReceive 很可能会得到 0。”

只要流是打开的，您就永远不会从 EndReceive 获得 0。您必须根据您的协议处理您获得的数据，以找到消息的结尾并发送响应。

正如您所要求的一些代码，这里是您的代码与 cmets 放置附加部分的位置：

If bytesRead > 0 Then
    ' There might be more data, so store the data received so far.
    state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead))

    ' Put here code to check for protocol end (for example \0) in your buffer state.sb
    ' and handle protocol if found. The rest of the buffer should remain in the buffer
    ' as it could be part of the next protocol.

    ' if you only except one message, set receiveDone.Set() here if message received
    ' completely

    '  Se supone que vuelve por los datos que faltan, pero no lo hace (Creo)
    client.BeginReceive(state.buffer, 0, state.BufferSize, 0, AddressOf OnRecieve, state)

Else
    'connection was closed
    ' handle existing information if appropreate
    receiveDone.Set()
End If