How to run one instance of a c# WinForm application?

Question

I\'ve a C# application that displays a login form when launched and displays the main form after users are authenticated. I used Mutex to restrict that only one instance of

Answer 1

If you are ok with a reference to Microsoft.VisualBasic, you can use its SingleInstance processing.

    [STAThread]
    static void Main(string[] args)
    {
        using (System.Threading.Mutex mutex = new System.Threading.Mutex(true, "MyApp.SingleInstance.Mutex", out createdNew))
        {
            MainForm = new MainDlg();
            SingleInstanceApplication.Run(MainForm, StartupNextInstanceEventHandler);
        }
    }

    public static void StartupNextInstanceEventHandler(object sender, StartupNextInstanceEventArgs e)
    {
        MainForm.Activate();
    }

public class SingleInstanceApplication : WindowsFormsApplicationBase
{
    private SingleInstanceApplication()
    {
        base.IsSingleInstance = true;
    }

    public static void Run(Form f, StartupNextInstanceEventHandler startupHandler)
    {
        SingleInstanceApplication app = new SingleInstanceApplication();
        app.MainForm = f;
        app.StartupNextInstance += startupHandler;
        app.Run(Environment.GetCommandLineArgs());
    }
}