Mutex bring back from minimized

Question

I am using mutex to check one instance at the time. It works, but to be perfect I need to fix one bug. If program is in minimized state it will not restore it self after I click Ok. Any ideas?

This is in Program.cs :

if (process.Id != current.Id)
{
    SetForegroundWindow(process.MainWindowHandle);
    MessageBox.Show(new Form1 { TopMost = true }, "Application is already running!");

    Form1 f1 = new Form1();

    f1.WindowState = FormWindowState.Normal; // dont work
    f1.BringToFront();                       // dont work
    f1.Focus();                              // dont work

    break;
}

Your f1 variable doesn't refer to your existing form, but rather a new one which is why setting properties on that variable have no effect. Are you trying to restore an existing form? If so you'll need to get a reference to it or use pinvoke if it's a form running in another instance of your application (which is what it sounds like) — pinkfloydx33, Jul 04 '18 at 08:44
The .NET Framework already knows how to do this automatically: https://stackoverflow.com/a/19326/17034 — Hans Passant, Jul 04 '18 at 09:21
Yes I want to restore existing one. What is the easiest way to get reference to it? — Vyt Autas, Jul 04 '18 at 11:51

score 0 · Answer 1 · answered Jul 04 '18 at 08:33

create an extension method:

using System.Runtime.InteropServices;

namespace System.Windows.Forms
{
    public static class Extensions
    {
        [DllImport( "user32.dll" )]
        private static extern int ShowWindow( IntPtr hWnd, uint Msg );

        private const uint SW_RESTORE = 0x09;

        public static void Restore( this Form form )
        {
            if (form.WindowState == FormWindowState.Minimized)
            {
                ShowWindow(form.Handle, SW_RESTORE);
            }
        }
    }
}

then use form.Restore() in your code.

Mutex bring back from minimized

1 Answers1