winform中已运行的程序则显示到桌面

static class Program

    {

        /// <summary>

        /// 应用程序的主入口点。

        /// </summary>

        [STAThread]

        static void Main()

        {

            Process instance = RunningInstance();

            if (instance == null)

            {

                //没有实例在运行

                Application.EnableVisualStyles();

                Application.SetCompatibleTextRenderingDefault(false);

                Application.Run(new Form1());

            }

            else

            {

                //已经有一个实例在运行

                HandleRunningInstance(instance);

            }

        }

 

         private static Process RunningInstance()

         {

             Process current = Process.GetCurrentProcess();

             Process[] processes = Process.GetProcessesByName(current.ProcessName);

             //遍历与当前进程名称相同的进程列表  

             foreach (Process process in processes)

             {

                 //如果实例已经存在则忽略当前进程  

                 if (process.Id != current.Id)

                 {

                     //保证要打开的进程同已经存在的进程来自同一文件路径

                     if (Assembly.GetExecutingAssembly().Location.Replace("/", "\\") == current.MainModule.FileName)

                     {

                         //返回已经存在的进程

                         return process;

                          

                     }

                 }

             }

             return null;

         }

 

         public static void HandleRunningInstance(Process instance)

         {

             ShowWindowAsync(instance.MainWindowHandle, WS_SHOWNORMAL);

             SetForegroundWindow(instance.MainWindowHandle);

         }

         [DllImport("User32.dll")]

         private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);

         [DllImport("User32.dll")]

         private static extern bool SetForegroundWindow(IntPtr hWnd);

         private const int WS_SHOWNORMAL = 1;

    }