How to focus WPF windows application from App.xaml.cs

Question

I know this may not be good practice, but still it is something I would like to implement.

I have a WPF windows application that I only want to run one instance of. If the user tries to start the program again a messagebox will show telling that the program is already running. This check is performed in app.xaml.cs.

So far so good. Everything works as expected.

I would like to expand this functionality to give focus and bring the mainwindow of the program to the front of the users desktop, over other windows and applications. I have tried numerous approaches, but can not get it to work. This should also happen in app.xaml.cs where I test if the application is already running.

It is not possible to do this in WPF? I have tried pinvokes and other stuff, but nothing seems to work for me.

Best regards

Nicki

Answer 1

I found a solution.

Adding a reference to VisualBasic gives access to Interactive.AppActivate, which can activate any process given a processid, which I already had implemented.

This page gave me the solution AppActivate In C#

I check for running process in the following manner

Process currentProcess = Process.GetCurrentProcess();
        var runningProcess = (from process in Process.GetProcesses()
                              where
                                process.Id != currentProcess.Id &&
                                process.ProcessName.Equals(
                                  currentProcess.ProcessName,
                                  StringComparison.Ordinal)
                              select process).FirstOrDefault();
        if (runningProcess != null)
        {
            Microsoft.VisualBasic.Interaction.AppActivate(runningProcess.Id);
            return;
        }

Answer 2

Have you tried activating it?

Application.Current.MainWindow.Activate();

Of course if you like it to stay on top at all times than:

Application.Current.MainWindow.Topmost = true;