Window's form

Are you using stand alone forms or an MDI interface?

What version?  .Net Framework 1.1 (or below) or 2.0?

stand alone forms and .Net Framework 1.1

Use this code (suppose this is winform program named "WindowsApplication")
//using statement
//add this
using System.Diagnostics;

//handle Form-Loadevent of form
this.Load += new System.EventHandler(this.Form1_Load);


private void Form1_Load(object sender, System.EventArgs e)
            {
                  if (Process.GetProcessesByName("WindowsApplication").Length > 1)
                        this.Close();
            }

Hope this help you.

Check out the singleton pattern:
https://www.experts-exchange.com/questions/20883192/Single-instance-of-a-form-class-URGENT-500-Points.html

(suppose this is winform program named "WindowsApplication")

this WindowsApplication is the project name or the form name ??

hmm ...

Idle_Mind i dun really understand that.

ok wat i did was. is this correct ?
i wanna access the fucntion to set config.active = true in trayform without creating another instance.

public TrayForm{
    private Configuration config;

     private void TrayForm_Load(object sender, System.EventArgs e)
    {
     config = new Configuration();
    }

     public static TrayForm Instance()
    {
          config.active = true;
     }
}





So instead of:

TrayFormmy tray = new TrayForm();

you would use:

TrayForm tray = TrayForm.Instance();


thanks

"WindowsApplication" is a project name.
My method is suitable for 1 application (1 or many forms) only exist 1 instance.
I think Idle_Mind's method is suitable for you.

thanks i will try it once i got the time =)