SingleInstanceCore 2.2.2

The class that handles instance invokation should inherit ISingleInstance and implement OnInstanceInvoked method.

WPF

E.g. in App class (App.xaml.cs):

public partial class App : Application, ISingleInstance
{
	public void OnInstanceInvoked(string[] args)
	{
		// What to do with the args another instance has sent
	}
	// ...
}

Initialization of instance should be done when application is starting, and cleanup method should be called on the exit point of the application.

E.g. in App class (App.xaml.cs):

	private void Application_Startup(object sender, StartupEventArgs e)
	{
		bool isFirstInstance = this.InitializeAsFirstInstance("soheilkd_ExampleIPC");
		if (!isFirstInstance)
		{
			//If it's not the first instance, arguments are automatically passed to the first instance
			//OnInstanceInvoked will be raised on the first instance
			//You may shut down the current instance
			Current.Shutdown();
		}
	}
		
	private void Application_Exit(object sender, ExitEventArgs e)
	{
		//Do not forget to cleanup
		SingleInstance.Cleanup();
	}

Winforms

Winforms doesn't have an Application.cs that could implement the ISingleInstance interface. We have to define one ourselves.

static class Program
{
	[STAThread]
	static void Main(string[] args)
	{
		var app = new YourApplication();

		var isFirstInstance = app.InitializeAsFirstInstance(nameof(YourApplication));
		if (isFirstInstance)
		{
			try
			{
				app.Run();
			}
			finally
			{
				SingleInstance.Cleanup();
			}
		}
	}
}

class YourApplication : ISingleInstance
{
	public void Run()
	{
		Application.SetHighDpiMode(HighDpiMode.SystemAware);
		Application.EnableVisualStyles();
		Application.SetCompatibleTextRenderingDefault(false);
		Application.Run(new MainForm()); // Blocks until the main window is closed
	}

	public void OnInstanceInvoked(string[] args)
	{
		// What to do with the args another instance has sent
	}
}