When use .net Mutex to ensure single instance, is that possible update first instance when launch second instance

Question

I have a winform application. the Mutex class used to block create more than one instance.

static class Program
{

    public static string IDFromAnotherApp = "default";
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main(string[] args)
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);

        if (args.Length > 0)
            IDFromAnotherApp = args[0];

        bool successAquisition;
        Mutex programMutex = new Mutex(true,
            AppDomain.CurrentDomain.SetupInformation.ApplicationName,
            out successAquisition);

        if (successAquisition)
        {
            Application.Run(new Form1());
            programMutex.ReleaseMutex();
            GC.KeepAlive(programMutex);

        }
        else
        {
            IDFromAnotherApp = "another";
            MessageBox.Show("already open");

        } 

    }
}

Form1 code

    public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();
        DisplayId();   
    }

    public void DisplayId()
    {
        label1.Text = Program.IDFromAnotherApp;
    }
}

Now when a user clicks the APP with a parameter, the Form1 label1 control will present that value, but if another user clicks the APP again, a pop up will say "already open"

I would like to do better, instead of pop up window, when another user clicks the APP with a parameter, can that already be opened Form1 update its label1's text? is that even possible?

Answer 1

You could use any one of number techinques

1. NamedPipes
2. Windows Messages
3. Windows sockets
4. WCF
5. lots more...

I would suggest NamedPipes or probably Windows Messages

As for exactly how to do this, there are plenty of examples on the internet and a good exercise for you to research. If you have a problem with any particular technique please feel welcome to ask another question on the specifics of your problem you are having