How can I prevent launching my app multiple times?

Question

I deployed my C# WinForms application using ClickOnce installation. Everything works fine with it (after a lot of work) :), but now I\'m facing a problem:

Whenever

Answer 1

solution in Windows form application Prohibit again run application(reopen application).

1- first add Class RunAlready.cs

2-Call method processIsRunning() with Name Process from RunAlready.cs in Program.cs

Program.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Tirage.MainStand
{
static class Program
{

    /// 

    /// The main entry point for the application.
    /// 
    [STAThread]
    static void Main()
    {
        PublicClass.Class.RunAlready RunAPP = new PublicClass.Class.RunAlready();
        string outApp = RunAPP.processIsRunning("Tirage.MainStand");

        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        MainStand_FrmLogin fLogin = new MainStand_FrmLogin();
        if (outApp.Length == 0)
        {

            if (fLogin.ShowDialog() == DialogResult.OK)
            {
                Application.Run(new MainStand_masterFrm());

            }
        }
        else MessageBox.Show( "Instance already running");

      }
    }
 }

class RunAlready:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace PublicClass.Class
{
  public  class RunAlready
    {
      public  string processIsRunning(string process)
        {
        string xdescription = "";
        System.Diagnostics.Process[] processes =
            System.Diagnostics.Process.GetProcessesByName(process);
        foreach (System.Diagnostics.Process proc in processes)
        {
            var iffffd = System.Diagnostics.Process.GetCurrentProcess().Id;
            if (proc.Id != System.Diagnostics.Process.GetCurrentProcess().Id)
            {
                xdescription = "Application Run At time:" + proc.StartTime.ToString() + System.Environment.NewLine;
                xdescription += "Current physical memory : " + proc.WorkingSet64.ToString() + System.Environment.NewLine;
                xdescription += "Total processor time : " + proc.TotalProcessorTime.ToString() + System.Environment.NewLine;
                xdescription += "Virtual memory size : " +         proc.VirtualMemorySize64.ToString() + System.Environment.NewLine;
            }
        }


        return xdescription;
    }
}
}