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C# Detect for start application twice time (advanced)

Hi experts!

Im using C# 2008 , WinForm NET 2. I have application, which if is started with command parameters start different forms (and this form stay open all the time and can not be change).
I want to make sure that this application can not be started twice on 1 computer. This is simple, but not in this case. Because in fact application is count if is started twice with same parametyr. (possible option are only 3 and are static text like param1 or param2 or param3 How to do this ?

In COM world I will ask and get for caption of application and will understand have or not have already started this application. But how I can do this via NET?

I can save let say in registry this info, but if my application fail it will not save that is close and next time is possible to be unable to start J

I need this to keep from people error with started twice time my application.

ASKER CERTIFIED SOLUTION

Dirk Haest

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Jaime Olivares

Have a look to:
http://www.codeproject.com/KB/cs/singleinstance.aspx

Rahul Goel

Hey this will help you.
http://en.csharp-online.net/Application_Architecture_in_Windows_Forms_2.0%E2%80%94Single-Instance_Detection_and_Management

you can use WindowsFormsApplicationBase class and check whether you appl has got different forms or not

retorikci

in your Program.cs try this code.
in this example we avoid Login twice times.

using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Runtime.InteropServices; 
 
    //static class Program
    //{
    //    /// <summary>
    //    /// The main entry point for the application.
    //    /// </summary>
    //    [MTAThread]
    //    static void Main()
    //    {
    //        try
    //        {
    //            Application.Run(new frmLogin());
    //        }
    //        catch (Exception ex)
    //        {
    //            MessageBox.Show(ex.ToString());
    //        }
    //    }
    //}
 
    static class Program
    {
        // need this for single instance detection 
        [DllImport("coredll.dll")]
        private static extern int FindWindow(string lpClassName, string lpWindowName);
        [DllImport("coredll.dll")]
        private static extern bool SetForegroundWindow(int hwnd);
 
        const string appName = "Login";
        const int ALREADY_EXISTS = 183;
        
        static void Main()
        {
            startTicks = Environment.TickCount;
 
            using (AppExecutionManager execMgr = new AppExecutionManager(appName))
            {
                if (execMgr.IsFirstInstance)
                    Application.Run(new frmLogin());
                else
                {
                    int hWnd = FindWindow(null, appName);
                    SetForegroundWindow(hWnd); 
                }
            }
        }
        internal static int startTicks;
    }

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