C# windows应用程序单实例运行实例

public class Program
    {
        private const int WS_SHOWNORMAL = 1;

        public const Int32 AW_BLEND = 0x00080000;
        [DllImport("User32.dll")]
        private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);
        [DllImport("User32.dll")]
        private static extern bool SetForegroundWindow(IntPtr hWnd);
        [DllImport("User32.dll")]
        private static extern bool AnimateWindow(IntPtr hwnd, int dwTime, int dwFlags);
        [DllImport("User32.dll", EntryPoint = "FindWindow")]
        private extern static IntPtr FindWindow(string lpClassName, string lpWindowName);

        [STAThread]
        static void Main()
        {
            Process instance = GetRunningInstance();
            if (instance == null)
            {
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new FrmRPAMsgLgn());
            }
            else
            {
                HandleRunningInstance(instance);
            }
        }

        public static Process GetRunningInstance()
        {
            Process current = Process.GetCurrentProcess();
            Process[] processes = Process.GetProcessesByName(current.ProcessName);

            foreach (Process process in processes)
            {
                if (process.Id != current.Id)
                    if (Assembly.GetExecutingAssembly().Location.Replace("/", "") == current.MainModule.FileName)
                        return process;
            }
            return null;
        }

        public static void HandleRunningInstance(Process instance)
        {
            if (instance.MainWindowHandle.ToInt32() != 0)
            {
                ShowWindowAsync(instance.MainWindowHandle, WS_SHOWNORMAL);
                SetForegroundWindow(instance.MainWindowHandle);
            }
            else
            {
                IntPtr hwnd = FindWindow(null, "MY Messenger");
                if (hwnd.ToInt32() == 0)
                    hwnd = FindWindow(null, "我的信使系统");
                //AnimateWindow(hwnd, 1000, AW_BLEND);
                ShowWindowAsync(hwnd, WS_SHOWNORMAL);
                SetForegroundWindow(hwnd);
            }
        }
    } 

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