WPF - Single Instance Application

In this blog I will show how to implement an single instance application:

To implement, I will use Microsoft.Visualbasic library (latest version is 10.0.0.0).

In your main project, create a class inherit from WindowsFormsApplicationBase

public class SingleApp : WindowsFormsApplicationBase
{

   //this is the actual App class (App.xaml)
   private App _app;

   public SingleApp()
   {
      IsSingleInstance = true;

   }

   protected override bool OnStartup(StartupEventArgs eventArgs)
   {
      try
      {
         _app = new App();
         _app.Run();
      }
      catch (Exception ex)
      {
         //do handle exception

      }

      return false;
   }

   protected override void OnStartupNextInstance(StartupNextInstanceEventArgs eventArgs)
   {

      //make the running application do something. Show main window for exsample
      _app.NextInstanceRun();
   }
}

SingleApp will act like a Application host.

Now we create a static Main() function to run this SingleApp

public class AppAccessPoint

{
   /// <summary>
   /// Mains the specified args.
   /// This is the real entry point, not the WPF APP
   /// </summary>
   /// <param name="args">The args.</param>
   [STAThread]
   public static void Main(string[] args)
   {

      SingleApp manager = new SingleApp();
      manager.Run(args);
   }
}

make sure to change the start up project to the Main function

  Done