Closing all Windows in a C# WPF application

Question

I'm creating a little WPF app in VS2013Express and I've come across a little problem. You see, there are three windows, MainWindow, LatAndLongDialog, TimeCitiesDialog.

`LatAndLongDialog` and `TimeCitiesDialog` are opened from MainWindow (with the click of a button). I want all the other windows to close when the `Closed()` event is called on `MainWindow`. The code on MainWindow.xaml.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace GlobalTime_ELITE_for_WPF
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            UserDescText.Content =
            "Select a TimeCity or enter the latitude and longitude in \n" +
            "to view the World Time there. Or, select another one of the\n" +
            "options below to do that. Go to Help by clicking on the link\n" +
            "on the upper-right corner of the window to view everything you\n" +
            "can do.";
            this.Closed += CloseOff;
        }
        private void OpenTimeCitiesDialog(Object Sender, EventArgs E)
        {
            TimeCitiesDialog ObjectReference = new TimeCitiesDialog();
            ObjectReference.Show();
        }
        private void OpenLatAndLongDialog(Object Sender, EventArgs E)
        {
            LatAndLongDialog ObjectReference = new LatAndLongDialog();
            ObjectReference.Show();
        }
        private void CloseOff(Object Sender, EventArgs E)
        {
            this.Close();
            TimeCitiesDialog tcdor = new TimeCitiesDialog();
            LatAndLongDialog laldor = new LatAndLongDialog();
        }
    }
}

How can I close them all? Please help!

Answer 1

The proper way to shutdown a WPF app is to use Application.Current.Shutdown() . This will close all open Windows, raise some events so that cleanup code can be run, and it can't be canceled. Environment.Exit() terminates the application immediately even if other threads are executing.

You should also consider setting the Owner on non-main Windows. The behavior will likely be more like what you would expect in regards to Z-order, minimizing, and maximizing. As an added bonus, the owned windows will automatically close when the owner Window closes.