WPF application without loading a window automatically issue

Question

I have set up a WPF application so that it does not load a window automatically by modifying the app.xaml.cs as shown below and by setting the build action to Page. I have also removed the starturl from the app.xaml. I have introduced a controller class from where the application starts as you can see in the code below and in the constructor for the controller I have created and opened a new window. I deleted the original MainWindow which was produced automatically when opening the application.

Anyway the problem is that after opening the new window that I have added in the controller I then close the window and the Application terminates? Why? I don't want the application to terminate and I don't understand why it is terminating on closing the window. Or to put it another way how can I introduce a window that doesn't cause the application to terminate on closing the window? Any help greatly appreciated.

using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;

namespace UserTraining
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        App()
        {
            InitializeComponent();
        }

        [STAThread]
        static void Main()
        {            
            App app = new App();
            UserTrainingController control = new UserTrainingController();
            app.Run();
        }

    }
}

UserTrainingController class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace UserTraining
{
    class UserTrainingController
    {
        public UserTrainingController()
        {
            IntroductionWindow w = new IntroductionWindow();
            w.Show();
        }
    }
}

Steven Rands Steven Rands · Accepted Answer · 2018-10-03T09:07:53

A WPF application has a ShutdownMode property, whose value is one of the members of the ShutdownMode enumeration. This has three possible values: OnExplicitShutdown, OnLastWindowClose and OnMainWindowClose.

The default is set to OnLastWindowClose which means that the application will shutdown when either the last window closes, or Application.Shutdown() is called. I suspect this is why your application terminates when your IntroductionWindow is closed.

What you need to do is set ShutdownMode to OnExplicitShutdown instead. That way, your application will only terminate when you explicitly call Application.Shutdown().

You can set the ShutdownMode property either in code or in your App.xaml file.

WPF application without loading a window automatically issue

2 Answers