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C# Detect for start application twice time (advanced)

Posted on 2009-07-02
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Last Modified: 2013-12-17
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.
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Question by:dvplayltd
4 Comments
 
LVL 53

Accepted Solution

by:
Dhaest earned 500 total points
ID: 24770285
Ensuring that only a single instance of a .NET application is running
http://www.ai.uga.edu/~mc/SingleInstance.html

[STAThread]

    static void Main()                  // args are OK here, of course

    {

        bool ok;

        m = new System.Threading.Mutex(true, "YourNameHere", out ok);
 

        if (! ok)

        {

            MessageBox.Show("Another instance is already running.");

            return;

        }
 

        Application.Run(new Form1());   // or whatever was there
 

        GC.KeepAlive(m);                // important!

    }

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LVL 55

Expert Comment

by:Jaime Olivares
ID: 24770350
0
 
LVL 9

Expert Comment

by:Rahul Goel
ID: 24770497
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
0
 
LVL 2

Expert Comment

by:retorikci
ID: 24770924
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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