监听UDP接收指令，实现再次启动则弹出已启动的

Netch/Forms/MainForm.cs

@@ -51,6 +51,7 @@ namespace Netch.Forms
 
         private void MainForm_Load(object sender, EventArgs e)
         {
+            OnlyInstance.Called += OnCalled;
             // 计算 ComboBox绘制 目标宽度
             _eWidth = ServerComboBox.Width / 10;
 
@@ -107,6 +108,21 @@ namespace Netch.Forms
             });
         }
 
+        private void OnCalled(object sender, OnlyInstance.Commands e)
+        {
+            switch (e)
+            {
+                case OnlyInstance.Commands.Show:
+                    NotifyIcon_MouseDoubleClick(null, null);
+                    break;
+                case OnlyInstance.Commands.Exit:
+                    Exit(true);
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(e), e, null);
+            }
+        }
+
 
         private void MainForm_FormClosing(object sender, FormClosingEventArgs e)
         {

Netch/Models/Setting.cs

@@ -124,6 +124,11 @@ namespace Netch.Models
         /// </summary>
         public int RedirectorTCPPort = 3901;
 
+        /// <summary>
+        ///		UDP Socket 占用端口
+        /// </summary>
+        public int UDPSocketPort = 18291;
+
         /// <summary>
         ///		HTTP 和 Socks5 本地代理地址
         /// </summary>

Netch/Netch.cs

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Threading;
+using System.Threading.Tasks;
 using System.Windows.Forms;
 using Netch.Controllers;
 using Netch.Forms;
@@ -65,13 +66,14 @@ namespace Netch
                 // 检查是否已经运行
                 if (!mutex.WaitOne(0, false))
                 {
-                    // 弹出提示
-                    MessageBoxX.Show(i18N.Translate("Netch is already running"));
+                    OnlyInstance.Send(OnlyInstance.Commands.Show);
 
                     // 退出进程
                     Environment.Exit(1);
                 }
 
+                Task.Run(OnlyInstance.Server);
+
                 // 绑定错误捕获
                 Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);
                 Application.ThreadException += Application_OnException;

Netch/Utils/OnlyInstance.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+
+namespace Netch.Utils
+{
+    public class OnlyInstance
+    {
+        public enum Commands
+        {
+            Show,
+            Exit
+        }
+        
+        public static event EventHandler<Commands> Called;
+
+        private static void OnCalled(Commands e)
+        {
+            Called?.Invoke(null, e);
+        }
+
+        public static async void Server()
+        {
+            try
+            {
+                if (PortHelper.PortInUse(Global.Settings.UDPSocketPort))
+                {
+                    Global.Settings.UDPSocketPort = PortHelper.GetAvailablePort();
+                    Configuration.Save();
+                }
+
+                var data = new byte[1024];
+                var newsock = new UdpClient(new IPEndPoint(IPAddress.Loopback, Global.Settings.UDPSocketPort));
+
+                while (true)
+                {
+                    var result = await newsock.ReceiveAsync();
+                    data = result.Buffer;
+                    if (Enum.TryParse<Commands>(Encoding.ASCII.GetString(data, 0, data.Length), out var command))
+                    {
+                        OnCalled(command);
+                    }
+                }
+            }
+            catch (Exception e)
+            {
+                Logging.Error(e.ToString());
+            }
+        }
+
+        public static async void Send(Commands command)
+        {
+            try
+            {
+                using (var udpClient = new UdpClient(Global.Settings.UDPSocketPort))
+                {
+                    udpClient.Connect(IPAddress.Loopback, Global.Settings.UDPSocketPort);
+                    var sendBytes = Encoding.ASCII.GetBytes(command.ToString());
+                    await udpClient.SendAsync(sendBytes, sendBytes.Length);
+
+                    udpClient.Close();
+                }
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine(e.ToString());
+            }
+        }
+    }
+}

Netch/Utils/PortHelper.cs

@@ -111,6 +111,20 @@ namespace Netch.Utils
 
             return isPortExcluded && (isTcpUsed || isUdpUsed);
         }
+
+        public static int GetAvailablePort()
+        {
+            for (var i = 0; i < 55535; i++)
+            {
+                var p = new Random().Next(10000, 65535);
+                if (!PortInUse(p))
+                {
+                    return p;
+                }
+            }
+
+            throw new Exception("Cant Generate Available Port");
+        }
     }
 
     /// <summary>