TCP发送数据并得到响应什么都不返回

如何解决TCP发送数据并得到响应什么都不返回

我想在向服务器发送数据后立即得到数据响应，这是我的代码，NetworkStream.DataAvailable 总是返回 false，我无法从 NetworkStream 读取数据：

Public Async Function SendAndGetReply(ByVal data() As Byte,Optional ByVal timeout As Integer = 1000) As Task(Of Byte())
    Dim buffer(4095) As Byte
    Dim bytesRead As Integer = 0
    Dim stream As NetworkStream = client.GetStream()
    Using writeCts = New CancellationTokenSource(timeout)
        Await stream.WriteAsync(data,data.Length,writeCts.Token)
        Await stream.FlushAsync()
        Try
            Using memoryStream As New MemoryStream()
                Do
                    Debug.Print(stream.DataAvailable.ToString)
                    bytesRead = Await stream.ReadAsync(buffer,buffer.Length)
                    memoryStream.Write(buffer,bytesRead)
                Loop While bytesRead = 0
            End Using
        Catch ex As Exception
            Debug.Print(ex.Message.ToString)
        End Try
    End Using
    Return buffer.Take(bytesRead).ToArray
End Function

全班：

Public Delegate Sub TcpClientsEventHandler(Of TEventArgs)(ByVal sender As Object,ByVal e As TEventArgs)
Public Delegate Sub TcpClientsEventHandler(ByVal sender As Object)
Private client As TcpClient
Private listener As TcpListener
Private tasks As New List(Of Task)()
Public Event OnConnect As TcpClientsEventHandler
Public Event Ondisconnect As TcpClientsEventHandler
Public Event OnDataReceived As TcpClientsEventHandler(Of Byte())
Public BufferSize As Integer = 4096

Public ReadOnly Property RemoteEndPoint() As EndPoint
    Get
        If client Is nothing Then
            Throw New InvalidOperationException("Client is not connected")
        End If
        Return client.Client.RemoteEndPoint
    End Get
End Property

Private Sub New(ByVal client As TcpClient)
    Me.client = client
End Sub

Public Sub New(ByVal hostname As String,ByVal port As Integer)
    CheckServerUsedAsClient()
    CheckClientAlreadyConnected()
    client = New TcpClient()
    client.Connect(hostname,port)
    client.NoDelay = True
    CallOnConnect()
    StartReceiveFrom()
End Sub
Public Sub Connect(ByVal address As IPAddress,ByVal port As Integer)
    CheckServerUsedAsClient()
    CheckClientAlreadyConnected()
    client = New TcpClient()
    client.Connect(address,port)
    CallOnConnect()
    StartReceiveFrom()
End Sub
Public Sub disconnect()
    CheckServerUsedAsClient()
    CallOndisconnect()
    client.Close()
End Sub
Public Sub Start(ByVal port As Integer)
    Start(IPAddress.Any,port)
End Sub
Public Sub Start(ByVal address As IPAddress,ByVal port As Integer)
    CheckClientUsedAsServer()
    CheckServerAlreadyStarted()
    listener = New TcpListener(address,port)
    listener.Start()
    StartListen()
End Sub
Public Sub Close()
    CheckClientUsedAsServer()
    listener.Stop()
    Task.WhenAll(tasks).Wait()
End Sub

Public Sub SendData(ByVal data() As Byte)
    CheckServerUsedAsClient()
    client.GetStream().Write(data,data.Length)
End Sub

Private Sub CallOnDataReceived(ByVal data() As Byte)
    RaiseEvent OnDataReceived(Me,data)
End Sub
Private Sub CallOnConnect()
    RaiseEvent OnConnect(Me)
End Sub
Private Sub CallOndisconnect()
    RaiseEvent Ondisconnect(Me)
End Sub

Private Sub CheckServerUsedAsClient()
    If listener IsNot nothing Then
        Throw New InvalidOperationException("Cannot use a server connection as a client")
    End If
End Sub
Private Sub CheckClientUsedAsServer()
    If client IsNot nothing Then
        Throw New InvalidOperationException("Cannot use a client connection as a server")
    End If
End Sub
Private Sub CheckServerAlreadyStarted()
    If listener IsNot nothing Then
        Throw New InvalidOperationException("Server is already started")
    End If
End Sub
Private Sub CheckClientAlreadyConnected()
    If client IsNot nothing Then
        Throw New InvalidOperationException("Client is already connected")
    End If
End Sub

Private Sub StartListen()
    tasks.Add(ListenAsync())
End Sub
Private Async Function ListenAsync() As Task
    Do
        Dim client As TcpClient = Await listener.AcceptTcpClientAsync()
        Dim connection As New TcpClients(client)
        StartReceiveFrom()
        RaiseEvent OnConnect(Me)
    Loop
End Function

Private Sub StartReceiveFrom()
    tasks.Add(ReceiveFromAsync())
End Sub
Private Async Function ReceiveFromAsync(Optional ByVal timeout As Integer = 5000) As Task
    Try
        client.Client.ReceiveTimeout = timeout
        Dim stream As NetworkStream = client.GetStream()
        Dim buffer(BufferSize - 1) As Byte
        Dim ms As New MemoryStream()
        do while client.Client.Connected
            Dim bytesRead As Integer = Await stream.ReadAsync(buffer,buffer.Length)
            ms.Write(buffer,bytesRead)
            If Not stream.DataAvailable Then
                CallOnDataReceived(ms.ToArray())
                ms.Seek(0,SeekOrigin.Begin)
                ms.SetLength(0)
            End If
        Loop
    Catch
    End Try

End Function
Public Async Function SendAndGetReply(ByVal data() As Byte,bytesRead)
                Loop While bytesRead = 0
            End Using
        Catch ex As Exception
            Debug.Print(ex.Message.ToString)
        End Try
    End Using
    Return buffer.Take(bytesRead).ToArray
End Function

结束课程