WPF - Show an application hidden but active in the Task Manager

I would like to set up a persistent state for my application. Let me explain. The startup time is kinda long (mostly due to many database requests to a remote server, which take 5 - 10 seconds, and even more since my users usually have too much applications running...) and I'd like to set up a way to hide & show my application when needed.

What I am doing now is to only reduce app to tray when user clicks on the red cross. (The application really exits only when a user chooses File -> Exit).

All users are launching an installer which is checking the version installed, then the version available online, and update the app if needed before launching it.

Now, I'd like it to first check 开发者_如何学JAVAon the process monitor (the one found in Task Manager, Processes tab), and if a process is already running for the application, it'll just show the window again. Otherwise, if no process is running, we can process the classic-check-for-update-then-launch steps. This would especially remove a lot of stupid customer requests I regularly have ("hey, your application takes too long to load, so I clicked on it again 5 times and it launched 6 instances!!!!" :/ ) and therefore save me a lot of useless time spent asking them to stop launching 50 instances of the same application cause it won't make it any faster...

So my main question is: how to perform such a trick in C#/WPF? For now, my minimization process is kinda simple (even though maybe too simple): I just hide the window & the task bar entry. Now I don't know how to show it back from my installer

Any ideas?

Your customers' requests can never be stupid - they pay you money.

To bring window to front - create system wide mutex and check its presence on application startup. If it's there - use interprocess communication mechanisms to send message to that other instance to bring its main window to front (a window message or named pipe - both are fine). Here is an example (make sure to check related answers too).

And by any means show splash screen as soon as you can to prevent relaunching application again and again. If it does not appear in 1-2 seconds (2 is too long) it's bad. Responsiveness of your application makes feeling like it works faster.

Is it something like this you're looking for?

foreach (var p in Process.GetProcesses()) 
{
    if (p.ProcessName.Contains("myProcess"))
    {
        //process is already running
    }
}

Or, with LINQ:

if (Process.GetProcesses().Where(p => p.ProcessName.Contains("myProcess")).Any())
{
    //process is already running
}

If the users complain about startup times, maybe consider checking the version on exit, instead of startup.

I have answered a very similar question yesterday. The only bit that's missing there is how to hide and show the window: use Window.Visibility, set it to Visibility.Hidden to hide the window and to Visibility.Visible to show it again.