UDPClient接收问题...... [英] UDPClient Receive problem...

问题描述

您好，

我无法使用UdpClient套接字向本地PC上的端口发送数据或从本地PC上的端口接收数据。代码如下，在问题点发表评论（预先为任何信息提供thabnks）：

Private Sub TestUDP（）

Hello,

I'm having trouble using a UdpClient socket to send and receive data to/from a port on my local PC. The code is as follows, with comments at the problem spot (and thabnks in advance for any info):

Private Sub TestUDP()

'正确设置。
Const MY_LOCAL_IP_ADDRESS As String =" 192.168.1.203"

        'Set appropriately.
        Const MY_LOCAL_IP_ADDRESS As String = "192.168.1.203"

Dim udpSocket As System.Net.Sockets.UdpClient
Dim b（）As Byte
Dim remoteEndPoint As System.Net.IPEndPoint = Nothing

        Dim udpSocket As System.Net.Sockets.UdpClient
        Dim b() As Byte
        Dim remoteEndPoint As System.Net.IPEndPoint = Nothing

'创建udp客户端套接字。允许3秒读取响应。
udpSocket = New System.Net.Sockets.UdpClient
udpSocket.Client.ReceiveTimeout = 3000
udpSocket.Client.Bind（New System.Net.IPEndPoint（System.Net。 IPAddress.Parse（" 0.0.0.0"），0））

        'Create udp client socket. Allow 3 second response for reads.
        udpSocket = New System.Net.Sockets.UdpClient
        udpSocket.Client.ReceiveTimeout = 3000
        udpSocket.Client.Bind(New System.Net.IPEndPoint(System.Net.IPAddress.Parse("0.0.0.0"), 0))

'要发送的数据。
b = System.Text.Encoding.ASCII.GetBytes（" Whatever你想在这里""

        'Data to send.
        b = System.Text.Encoding.ASCII.GetBytes("Whatever you want here")

'发送到在这台PC上运行的另一个应用程序，在端口1757上侦听数据。它被写入以便回送数据。
udpSocket.Send（ b，b.Length，New System.Net.IPEndPoint（System.Net.IPAddress.Parse（MY_LOCAL_IP_ADDRESS），1757））

        'Send to another app running on this PC, listening for data on port 1757. It is written so that it echos data back.
        udpSocket.Send(b, b.Length, New System.Net.IPEndPoint(System.Net.IPAddress.Parse(MY_LOCAL_IP_ADDRESS), 1757))

试试
b = udpSocket.Receive（remoteEndPoint）

        Try
            b = udpSocket.Receive(remoteEndPoint)

'上面的线路：
'System.Net.Sockets.SocketException：远程主机强行关闭现有连接。
''但是......如果你将'MY_LOCAL_IP_ADDRESS的最不重要的八位字节改为255，或者局域网上的某些其他非本地IP，一切都很好。它只是不喜欢localhost IP。

            'THE ABOVE LINE THROWS:
            'System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host.
            '
            ' But...if you change the least significant octet of
            'MY_LOCAL_IP_ADDRESS to 255, or some other non-local IP on the
            'LAN, all is well. It just doesn't like the localhost IP.

Console.WriteLine（System.Text.Encoding.ASCII.GetString（b，0，b.Length））
Catch ex As System.Net.Sockets.SocketException
Console.WriteLine（ex.ToString）
End Try

            Console.WriteLine(System.Text.Encoding.ASCII.GetString(b, 0, b.Length))
        Catch ex As System.Net.Sockets.SocketException
            Console.WriteLine(ex.ToString)
        End Try

End Sub

推荐答案

也许你有防火墙阻止你进行udp连接

maybe you have a firewall preventing you to make an udp connection

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