在写上位机过程中需要写一个UDP持续监听的功能，实现方式选择新建while循环进程的方法。但是调试过程中发现，关闭界面后，线程还在后台持续运行。经查询资料，最终选择Thread的IsBackground属性来实现应用退出时自动结束线程。
线程开启后默认为前台线程，如果关闭应用，此线程不会关闭，会在系统持续运行直到此线程运行结束（本例中需要持续监听，所以线程开启了while(true)无限循环，如果主应用不abort，线程自己不会结束）。设置IsBackground属性为true后，关闭应用，此线程自动终止。
由于项目很大，在此只贴出能够展现此博文表述问题的代码块。
// This constructor arbitrarily assigns the local port number. UdpClient udpClient = null; Thread thread; private void BUTTudpConnect_Click(object sender, EventArgs e) { if (BUTTudpConnect.Text == "connect") { udpClient = new UdpClient(Convert.ToInt32(TBLocalPort.Text)); try { udpClient.Connect(TBRemoteIP.Text, Convert.ToInt32(TBRemotePort.Text)); UdpSend( udpClient); thread = new Thread(UdpListing); thread.Start(udpClient); thread.IsBackground = true; } catch (Exception ex) { MessageBox.Show(ex.ToString()); } BUTTudpConnect.Text = "disconnect"; } else { thread.Abort(); BUTTudpConnect.Text = "connect"; udpClient.Close(); } } private void UdpListing(Object obj) { UdpClient udpClient; udpClient = (UdpClient)obj; //IPEndPoint object will allow us to read datagrams sent from any source. IPEndPoint RemoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0); while(true) { // Blocks until a message returns on this socket from a remote host. Byte[] receiveBytes = udpClient.Receive(ref RemoteIpEndPoint); string returnData = Encoding.ASCII.GetString(receiveBytes); // Uses the IPEndPoint object to determine which of these two hosts responded. MessageBox.Show("This is the message you received " + returnData.ToString()); } }