How to ensure single instance application (on multiple virtual desktops)?

Question

I'm writing a C# WinForms application that I need to ensure there's a single instance running at any given time. I thought I had it working using a Mutex.

Here is a link that I found : How to restrict the application to just one instance.

This worked fine when I'm using a single desktop. However, when there are several virtual desktops open in Windows 10, each of those desktops can host another instance of the application.

Is there a way of limiting a single instance across ALL desktops?

Answer 1

If you look at Remarks section of the docs (see Note block) - you can see, that all you have to do is to prefix your mutex with "Global\". Here is an example for WinForms:

// file: Program.cs
[STAThread]
private static void Main()
{
    using (var applicationMutex = new Mutex(initiallyOwned: false, name: @"Global\MyGlobalMutex"))
    {
        try
        {
            // check for existing mutex
            if (!applicationMutex.WaitOne(0, exitContext: false))
            {
                MessageBox.Show("This application is already running!", "Already running",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }
        }
        // catch abandoned mutex (previos process exit unexpectedly / crashed)
        catch (AbandonedMutexException exception) { /* TODO: Handle it! There was a disaster */ }

        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new MainForm());
    }
}