c# - WPF App Doesn't Shut Down When Closing Main Window

Question

I'm used to WinForms programming in Visual Studio, but I wanted to give WPF a try.

I added another window to my project, called Window01. The main window is called MainWindow. Before the public MainWindow() constructor I declare Window01:

Window01 w1;

Now I instantiate this window in:

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    w1 = new Window01();            
}

I have a button where the window is shown: w1.ShowDialog();.

The 'funny' thing here is the fact that if I start the application (with debugging) and exit it a few seconds after (I don't do anything in the application), Visual Studio doesn't stop debugging as if the application is still running.

If I move the line w1 = new Window01(); to the button click method, meaning just above ShowDialog(), Visual Studio is behaving properly - that is, the debugging stops when I exit the application.

Why this strange behaviour?

Answer 1

In your MainWindow.xaml.cs, try doing this:

protected override void OnClosed(EventArgs e)
{
    base.OnClosed(e);

    Application.Current.Shutdown();
}

Per this link, you can also set the ShutdownMode in XAML:

http://msdn.microsoft.com/en-us/library/system.windows.application.shutdownmode.aspx

<Application
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    StartupUri="MainWindow.xaml"
    ShutdownMode="OnExplicitShutdown"
    >
</Application>

Applications stop running only when the Shutdown method of the Application is called. Shut down can occur implicitly or explicitly, as specified by the value of the ShutdownMode property.

If you set ShutdownMode to OnLastWindowClose, Windows Presentation Foundation (WPF) implicitly calls Shutdown when the last window in an application closes, even if any currently instantiated windows are set as the main window (see MainWindow).

A ShutdownMode of OnMainWindowClose causes WPF to implicitly call Shutdown when the MainWindow closes, even if other windows are currently open.

The lifetime of some applications may not be dependent on when the main window or last window is closed, or may not be dependent on windows at all. For these scenarios you need to set the ShutdownMode property to OnExplicitShutdown, which requires an explicit Shutdown method call to stop the application. Otherwise, the application continues running in the background.

ShutdownMode can be configured declaratively from XAML or programmatically from code.

This property is available only from the thread that created the Application object.

---

In your case, the app isn't closing because you're probably using the default OnLastWindowClose:

If you set ShutdownMode to OnLastWindowClose, WPF implicitly calls Shutdown when the last window in an application closes, even if any currently instantiated windows are set as the main window (see MainWindow).

Since you're opening a new window, and not closing it, shutdown doesn't get called.