检查客户端是否在tcp连接中关闭

时间:2016-05-18 23:25:44

标签: vb.net tcp server client

我对使用套接字和TCP非常陌生,而且我试图确定我的客户端和服务器之间的连接是否已关闭,这让我很茫然。

我当前的方法是在我结束连接时将我的字节数组的第一个元素(b(10)简单地用于写入和读取流)更改为0x0服务器端,然后检查是否第一个字节数组是0x0服务器端,以查看客户端是否已关闭。

我对此非常不满意,理想情况下我希望能够检查它的连接,但我找不到任何方法。

现在这只是用来从客户端发送几个字符的字符串并在服务器窗口上打印出来,但理想的是当我更了解我的内容时我想继续这样做。做。

服务器:

While True
    client.GetStream.Read(b, 0, 10)
    If b(0) <> Convert.ToByte(0) Then
        For i = 0 To 10
            Console.Write(Convert.ToChar(b(i)))
        Next i
        Console.Write(vbCrLf)
    Else
        Exit While
    End If
End While

客户端:

If aString = "y" Then
    'Create a TcpClient.
    client = New TcpClient(localAddr.ToString, port)
    Do
        Array.Clear(b, 0, 10)
        b(0) = 1
        Console.Write("Ready to quit? (y/message)")
        aString = Console.ReadLine()
        If aString <> "y" Then
            For i = 0 To Len(aString.ToCharArray()) - 1
                Console.WriteLine(i)
                b(i) = Convert.ToByte(aString.ToCharArray.GetValue(i))
            Next i
            client.GetStream.Write(b, 0, 10)
        End If
    Loop Until aString = "y"
    b(0) = Convert.ToByte(0)
    client.GetStream.Write(b, 0, 10)
    client.GetStream.Close()
    client.Close()
End If

任何人都可以提供有关如何以较少杂乱的方式执行此操作的详细信息,或者指出一些可能有用的资源吗?

1 个答案:

答案 0 :(得分:0)

查看How to check the connection state of a TCP Server (Socket) with TCP Client in VB.NET的答案我添加了以下功能:

Public Function IsConnected(ByRef client As TcpClient) As Boolean
    Try
        Return Not (client.Client.Poll(-1, SelectMode.SelectRead) _
                 AndAlso client.Available = 0)
    Catch ex As Exception
        Return False
    End Try
End Function

将服务器调整为:

While True
    If IsConnected(client) Then
        client.GetStream.Read(b, 0, 10)
        For i = 0 To 10
            Console.Write(Convert.ToChar(b(i)))
        Next i
        Console.Write(vbCrLf)
    Else
        Exit While
    End If
End While

客户:

If aString = "y" Then
    'Create a TcpClient.
    client = New TcpClient(localAddr.ToString, port)
    Do
        Array.Clear(b, 0, 10)
        Console.Write("Ready to quit? (y/message)")
        aString = Console.ReadLine()
        If aString <> "y" Then
            For i = 0 To Len(aString.ToCharArray()) - 1
                Console.WriteLine(i)
                b(i) = Convert.ToByte(aString.ToCharArray.GetValue(i))
            Next i
            client.GetStream.Write(b, 0, 10)
        End If
    Loop Until aString = "y"
    client.GetStream.Close()
    client.Close()
End If

现在工作正常。

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