Closing all Windows in a C# WPF application
<p>I'm creating a little WPF app in <code>VS2013Express</code> and I've come across a little problem.
You see, there are three windows, <code>MainWindow</code>, <code>LatAndLongDialog</code>, <code>TimeCitiesDialog</code>.</p>
<p></p>
`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:
<pre><code>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
{
    /// &lt;summary&gt;
    /// Interaction logic for MainWindow.xaml
    /// &lt;/summary&gt;
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            UserDescText.Content =
            &quot;Select a TimeCity or enter the latitude and longitude in \n&quot; +
            &quot;to view the World Time there. Or, select another one of the\n&quot; +
            &quot;options below to do that. Go to Help by clicking on the link\n&quot; +
            &quot;on the upper-right corner of the window to view everything you\n&quot; +
            &quot;can do.&quot;;
            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();
        }
    }
}
</code></pre>
<p>How can I close them all? Please help!</p>