Question

我有使用TCP连接从客户端向服务器发送字符串的代码。但我不知道如何将其转换为NonBlocking TCP状态连接。我试着把socket.Blocking = FALSE，但那段代码给我一个错误。

套接字错误代码：10035

异常标题：无法立即完成非阻塞套接字操作

这是我从客户端向服务器发送字符串的代码。

服务器代码：

Imports System.Net
Imports System.Net.Sockets
Imports System.Text

Module Module1
    Dim soket As Socket
    Sub Main()
        Try
            Dim alamatIP As IPAddress = IPAddress.Parse("127.0.0.1")
            Dim tcpListener As New TcpListener(alamatIP, 8000)
            'soket.Blocking = False - THIS WILL GIVE ME AN ERROR
            tcpListener.Start()

            System.Console.WriteLine("Server port 8000...")

            Dim myendpoint As IPEndPoint
            myendpoint = CType(tcpListener.LocalEndpoint, IPEndPoint)

            System.Console.WriteLine("IP : " + myendpoint.Address.ToString + " and port is " + myendpoint.Port.ToString)
            System.Console.WriteLine("Waiting for connection !")

            soket = tcpListener.AcceptSocket()
            myendpoint = CType(soket.RemoteEndPoint(), IPEndPoint)

            System.Console.WriteLine("Receiving from " + myendpoint.Address.ToString())

            Dim bitData(100) As Byte
            Dim newString As String = ""
            Do
                Try
                    Dim size As Integer = soket.Receive(bitData)
                    newString = Encoding.ASCII.GetString(bitData)
                    Console.WriteLine(newString)
                    Array.Clear(bitData, 0, bitData.Length)
                Catch ex As Exception
                    Console.Write(ex.ToString())
                End Try
            Loop While newString <> "exit"
            soket.Close()
            tcpListener.Stop()
        Catch ex As Exception
            Console.WriteLine("Error ..." + ex.ToString())
        End Try
        Console.ReadLine()
    End Sub

End Module

客户代码：

Imports System.Net
Imports System.Net.Sockets
Imports System.Text
Imports System.IO
Imports System.Threading
Module Module1

    Sub Main()
        Try
            Dim tcpClient As New TcpClient 'creating the client
            Console.WriteLine("Connecting....")
            tcpClient.Connect("127.0.0.1", 8000) 'connecting the client the server
            'port is same as in the server
            Console.WriteLine("Connected")
            Console.WriteLine("Enter the string to be transmitted : ")

            Dim strMessage As String
            Dim stm As Stream
            Dim counter As Integer = 0

            Do

                stm = tcpClient.GetStream() 'getting the stream of the client
                Dim ascenc As New ASCIIEncoding
                strMessage = Console.ReadLine()
                Dim byteData() As Byte = ascenc.GetBytes(strMessage)
                Console.WriteLine("Transmitted ")
                stm.Write(byteData, 0, byteData.Length())

            Loop While strMessage <> "exit"

                    tcpClient.Close() 'closing the connection
        Catch ex As Exception
            Console.WriteLine("Error..." + ex.StackTrace.ToString()) 'writing the exception into the console
        End Try
    End Sub

End Module

感谢您的帮助。

Answer 1

当您尝试从非阻塞套接字读取或写入它并且此操作无法立即完成时，则套接字应该发出错误信号。在VB中，它意味着它应该引发异常。例如，当您的计算机未收到任何数据但您尝试Read某些内容时，会发生这种情况。

在非阻塞套接字上尝试操作之前，请调用Select或Poll以确保它已准备好进行操作。

VB.net TCP非阻塞状态

1 个答案: