WPF:实现主应用程序单一实例运行方式总结

   本文介绍常见的实现主应用程序单一实例运行的几种方式。

方式一：

    public partial class App : Application
    {
        protected override void OnStartup(StartupEventArgs e)
        {
            Process thisProc = Process.GetCurrentProcess();

            if (Process.GetProcessesByName(thisProc.ProcessName).Length > 1)
            {
                Application.Current.Shutdown();
                return;
            }
            base.OnStartup(e);
        }
    }

　　

方式二：

    public partial class App : Application
    {
        public static EventWaitHandle ProgramStarted;
        private bool CreatedNew;

        protected override void OnStartup(StartupEventArgs e)
        {
            ProgramStarted = new EventWaitHandle(false, EventResetMode.AutoReset, "MyApplication", out CreatedNew);
            if (CreatedNew)
            {
                MainWindow mainWindow = new MainWindow();
                this.MainWindow = mainWindow;
                mainWindow.Show();
            }
            else
            {
                ProgramStarted.Set();
                Environment.Exit(0);
            }
        }
    }

　

方式三:

    public partial class App : Application
    {
        private bool canCreateNew;
        private int EXISTINGWINGDOW_HANDLER;
        private Mutex m_ServerMutex;

        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);
            this.m_ServerMutex = new Mutex(true, "MyApplication", out this.canCreateNew);
            if (!this.canCreateNew)
            {
                try
                {
                    this.EXISTINGWINGDOW_HANDLER = SendMessageHelper.FindWindow(null, "WpfApplication1");
                    SendMessageHelper.SendMessage(this.EXISTINGWINGDOW_HANDLER, 0x112, 0xf120, 0);
                    Application.Current.Shutdown(-1);
                }
                catch
                {
                }
            }
        }
    }

    public static class SendMessageHelper
    {
        [DllImport("User32.dll")]
        public static extern int FindWindow(string lpClassName, string lpWindowName);
        [DllImport("User32.dll")]
        public static extern int SendMessage(int hWnd, int Msg, int wParam);
        [DllImport("User32.dll")]
        public static extern int SendMessage(int hWnd, int Msg, int wParam, int lParam);
        [DllImport("User32.dll")]
        public static extern int SendMessage(int hWnd, int Msg, int wParam, IntPtr lParam);
    }

　　

方式四：

注意：添加 Microsoft.VisualBasic.dll类库引用，并在项目属性窗口中设置启动对象为类MainEntry。

    public partial class App : Application
    {

    }

    public class MainEntry
    {
        [STAThread]
        static void Main(string[] args)
        {
            SingleInstanceManager manager = new SingleInstanceManager();
            manager.Run(args);
        }
    }

    public class SingleInstanceManager : Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase
    {
        App app;

        public SingleInstanceManager()
        {
            this.IsSingleInstance = true;
        }

        //应用程序初次运行时
        protected override bool OnStartup(Microsoft.VisualBasic.ApplicationServices.StartupEventArgs e)
        {
            try
            {
                app = new App();
                app.InitializeComponent();
                app.Run();
            }
            catch (Exception ex)
            {

            }
            return false;
        }

        //启动下一个应用程序实例时触发
        protected override void OnStartupNextInstance(Microsoft.VisualBasic.ApplicationServices.StartupNextInstanceEventArgs eventArgs)
        {
            base.OnStartupNextInstance(eventArgs);
        }
    }

　　

   对于单一实例运行，不得不提到主进程通知，就是说第二次启动应用程序时，如何发送消息？发送消息的方式有命令行方式和关联文件打开。如在cmd中输入 MyApplocation.exe somaParameters或者打开程序支持的文件（.myextension）。将在后续博客中进行归纳总结......