Question

Application c:\pinkPanther.exe is running and it is application i wrote in c#.
Some other application starts c:\pinkPanther.exe purpleAligator greenGazelle OrangeOrangutan and i would like not to start new instance of c:\pinkPanther.exe with these arguments, but to currently running c:\pinkPanther.exe register it and react to it somehow.

How to do it?

EDIT!!!: i’m very sorry about pinkPanther.exe and ruzovyJeliman.exe that caused the confusion – i translated question from my native language and missed it 🙁

Answer 1

To communicate with the other instance of the application, you need some sort of inter-process communication. Apparently, WCF is the recommended form of IPC in .Net. You can do that with code like this (using WPF, but WinForms would be similar):

[ServiceContract]
public interface ISingletonProgram
{
    [OperationContract]
    void CallWithArguments(string[] args);
}

class SingletonProgram : ISingletonProgram
{
    public void CallWithArguments(string[] args)
    {
        // handle the arguments somehow
    }
}

public partial class App : Application
{
    private readonly Mutex m_mutex;
    private ServiceHost m_serviceHost;
    private static string EndpointUri =
        "net.pipe://localhost/RuzovyJeliman/singletonProgram";

    public App()
    {
        // find out whether other instance exists
        bool createdNew;
        m_mutex = new Mutex(true, "RůžovýJeliman", out createdNew);

        if (!createdNew)
        {
            // other instance exists, call it and exit
            CallService();
            Shutdown();
            return;
        }

        // other instance does not exist
        // start the service to accept calls and show UI
        StartService();

        // show the main window here
        // you can also process this instance's command line arguments
    }

    private static void CallService()
    {
        var factory = new ChannelFactory<ISingletonProgram>(
            new NetNamedPipeBinding(NetNamedPipeSecurityMode.None), EndpointUri);

        var singletonProgram = factory.CreateChannel();
        singletonProgram.CallWithArguments(Environment.GetCommandLineArgs());
    }

    private void StartService()
    {
        m_serviceHost = new ServiceHost(typeof(SingletonProgram));
        m_serviceHost.AddServiceEndpoint(
            typeof(ISingletonProgram),
            new NetNamedPipeBinding(NetNamedPipeSecurityMode.None),
            EndpointUri);

        m_serviceHost.Open();
    }

    protected override void OnExit(ExitEventArgs e)
    {
        if (m_serviceHost != null)
            m_serviceHost.Close();

        m_mutex.Dispose();
        base.OnExit(e);
    }
}