Reduce code for back button

Author: ryanlua

AuraClick/MainWindow.xaml

@@ -22,7 +22,8 @@
         <TitleBar
             x:Name="AppTitleBar"
             x:Uid="AppTitleBar"
-            BackRequested="AppTitleBar_BackRequested">
+            BackRequested="TitleBar_BackRequested"
+            IsBackButtonVisible="{x:Bind RootFrame.CanGoBack, Mode=OneWay}">
             <TitleBar.IconSource>
                 <ImageIconSource ImageSource="Assets/AppIcon.ico" />
             </TitleBar.IconSource>
@@ -33,9 +34,6 @@
             MainPage.xaml rather than here so you can use Page features such as
             navigation events and the Loaded lifecycle.
         -->
-        <Frame
-            x:Name="RootFrame"
-            Grid.Row="1"
-            Navigated="RootFrame_Navigated" />
+        <Frame x:Name="RootFrame" Grid.Row="1" />
     </Grid>
 </windowex:WindowEx>

AuraClick/MainWindow.xaml.cs

@@ -45,16 +45,8 @@ public MainWindow()
         RootFrame.Navigate(typeof(MainPage));
     }
 
-    private void AppTitleBar_BackRequested(TitleBar sender, object args)
+    private void TitleBar_BackRequested(TitleBar sender, object args)
     {
-        if (RootFrame.CanGoBack)
-        {
-            RootFrame.GoBack();
-        }
-    }
-
-    private void RootFrame_Navigated(object sender, NavigationEventArgs e)
-    {
-        AppTitleBar.IsBackButtonVisible = e.SourcePageType != typeof(MainPage);
+        RootFrame.GoBack();
     }
 }