UdpClient.() vs UdpClient(port)

我有一个小问题和一个解决方案，但我想了解到底发生了什么。根据UdpClient的构造函数，我使用EndReceive()抛出一个套接字异常或不(10054 -一个现有的连接被远程主机关闭)

谢谢你的提示!文森特

private UdpClient udpClient;
    void recv(IAsyncResult res)
    {
        IPEndPoint remote = new IPEndPoint(IPAddress.Any, 0);
        byte[] data = udpClient.EndReceive(res, ref remote); // code stops here in debug
        // do something with data received from remote
        udpClient.BeginReceive(new AsyncCallback(recv), null);
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        //udpClient = new UdpClient(); // will throw exception
        udpClient = new UdpClient(8000); // will not throw exception
        udpClient.Connect("127.0.0.1", 8000);
        udpClient.BeginReceive(new AsyncCallback(recv), null);
    }
    private void button1_Click(object sender, EventArgs e)
    {
        udpClient.Send(Encoding.ASCII.GetBytes("Hallo"), 5);
    }