Add disabled Expander expanding/collapsing examples to the sample app

samples/ControlCatalog/Pages/ExpanderPage.xaml

@@ -52,6 +52,24 @@
         </StackPanel>
       </Expander>
       <CheckBox IsChecked="{Binding Rounded}">Rounded</CheckBox>
+      <Expander x:Name="CollapsingDisabledExpander"
+                Header="Collapsing Disabled"
+                IsExpanded="True"
+                ExpandDirection="Down"
+                CornerRadius="{Binding CornerRadius}">
+        <StackPanel>
+          <TextBlock>Expanded content</TextBlock>
+        </StackPanel>
+      </Expander>
+      <Expander x:Name="ExpandingDisabledExpander"
+                Header="Expanding Disabled"
+                IsExpanded="False"
+                ExpandDirection="Down"
+                CornerRadius="{Binding CornerRadius}">
+        <StackPanel>
+          <TextBlock>Expanded content</TextBlock>
+        </StackPanel>
+      </Expander>
     </StackPanel>
   </StackPanel>
 </UserControl>

samples/ControlCatalog/Pages/ExpanderPage.xaml.cs

@@ -10,6 +10,12 @@ namespace ControlCatalog.Pages
         {
             this.InitializeComponent();
             DataContext = new ExpanderPageViewModel();
+
+            var CollapsingDisabledExpander = this.Get<Expander>("CollapsingDisabledExpander");
+            var ExpandingDisabledExpander = this.Get<Expander>("ExpandingDisabledExpander");
+
+            CollapsingDisabledExpander.Collapsing += (s, e) => { e.Handled = true; };
+            ExpandingDisabledExpander.Expanding += (s, e) => { e.Handled = true; };
         }
 
         private void InitializeComponent()