WPF organization-mutex ensures application Singleton runs

Sometimes we do not want our WPF Application to run multiple instances at the same time. When we try to run the second instance, the running instance should also pop up.

We can use mutex to implement

Open app. XAML. CS and add the following content to the app class:

    public partial class App : Application    {        [DllImport("user32", CharSet = CharSet.Unicode)]        static extern IntPtr FindWindow(string cls, string win);        [DllImport("user32")]        static extern IntPtr SetForegroundWindow(IntPtr hWnd);        [DllImport("user32")]        static extern bool IsIconic(IntPtr hWnd);        [DllImport("user32")]        static extern bool OpenIcon(IntPtr hWnd);        protected override void OnStartup(StartupEventArgs e)        {            bool isNew;            var mutex = new Mutex(true, "My Singleton Instance", out isNew);            if (!isNew)            {                ActivateOtherWindow();                Shutdown();            }        }        private static void ActivateOtherWindow()        {            var other = FindWindow(null, "MainWindow");            if (other != IntPtr.Zero)            {                SetForegroundWindow(other);                if (IsIconic(other))                    OpenIcon(other);            }        }    }

 

The WPF implementation is slightly different from the winform implementation. See the previous blog post in debuglzq: using the kernel object mutex can prevent the same process from running twice.