How can I make sure only one WPF Window is open at a time?

Question

I have a WPF window that I am launching from inside of a winform app. I only want to allow once instance of that WPF window to be open at a time, and not warn that user if t

Answer 1

Rather than try to search for a Window instance, many people use a session- (or system-) wide "Mutex" or a Mutual Exclusion lock. I was going to rewrite one for you, but I found a good codeproject article demonstrating the technique. It's not complex and very simple.

http://www.codeproject.com/KB/cs/SingleInstanceAppMutex.aspx?msg=2908697

Sneak peek:

[STAThread]
static void Main()
{
    bool onlyInstance = false;
    Mutex mutex = new Mutex(true, "UniqueApplicationName", out onlyInstance);
    if (!onlyInstance) {
        return;
    }
    Application.Run(new MainForm);
    GC.KeepAlive(mutex);
}

Hope this helps.

(edit: of course you'll have to modify this slightly for your particular use-case, but it demos the general idea)