Add shell flyout scroll mode support (#12547) fixes #7913

xamarin · Nov 6, 2020 · ca423eb · ca423eb
1 parent afe2540
commit ca423eb
Show file tree

Hide file tree

Showing 2 changed files with 30 additions and 0 deletions.
diff --git a/Xamarin.Forms.Platform.UAP/Shell/ShellRenderer.cs b/Xamarin.Forms.Platform.UAP/Shell/ShellRenderer.cs
@@ -77,6 +77,7 @@ void OnPaneOpening(Microsoft.UI.Xaml.Controls.NavigationView sender, object args
 			UpdatePaneButtonColor(NavigationViewBackButton, false);
 			UpdateFlyoutBackgroundColor();
 			UpdateFlyoutBackdrop();
+			UpdateFlyoutVerticalScrollMode();
 		}
 
 		void OnPaneOpened(Microsoft.UI.Xaml.Controls.NavigationView sender, object args)
@@ -187,6 +188,7 @@ public void SetElement(VisualElement element)
 
 		#endregion IVisualElementRenderer
 		ShellSplitView ShellSplitView => (ShellSplitView)GetTemplateChild("RootSplitView");
+		ScrollViewer ShellLeftNavScrollViewer => (ScrollViewer)GetTemplateChild("LeftNavScrollViewer");
 		protected internal Shell Element { get; set; }
 
 		internal Shell Shell => Element;
@@ -210,6 +212,33 @@ protected virtual void OnElementPropertyChanged(object sender, PropertyChangedEv
 			{
 				UpdateFlyoutBackgroundColor();
 			}
+			else if (e.PropertyName == Shell.FlyoutVerticalScrollModeProperty.PropertyName)
+			{
+				UpdateFlyoutVerticalScrollMode();
+			}
+		}
+
+		void UpdateFlyoutVerticalScrollMode()
+		{
+			var scrollViewer = ShellLeftNavScrollViewer;
+			if (scrollViewer != null)
+			{
+				switch (Shell.FlyoutVerticalScrollMode)
+				{
+					case ScrollMode.Disabled:
+						scrollViewer.VerticalScrollMode = Windows.UI.Xaml.Controls.ScrollMode.Disabled;
+						scrollViewer.VerticalScrollBarVisibility = Windows.UI.Xaml.Controls.ScrollBarVisibility.Hidden;
+						break;
+					case ScrollMode.Enabled:
+						scrollViewer.VerticalScrollMode = Windows.UI.Xaml.Controls.ScrollMode.Enabled;
+						scrollViewer.VerticalScrollBarVisibility = Windows.UI.Xaml.Controls.ScrollBarVisibility.Visible;
+						break;
+					default:
+						scrollViewer.VerticalScrollMode = Windows.UI.Xaml.Controls.ScrollMode.Auto;
+						scrollViewer.VerticalScrollBarVisibility = Windows.UI.Xaml.Controls.ScrollBarVisibility.Auto;
+						break;
+				}
+			}
 		}
 
 		void UpdateFlyoutBackdrop()

diff --git a/Xamarin.Forms.Platform.UAP/Shell/ShellStyles.xaml b/Xamarin.Forms.Platform.UAP/Shell/ShellStyles.xaml
@@ -476,6 +476,7 @@
                                             HorizontalAlignment="Stretch"
                                             VerticalAlignment="Top">
                                             <ScrollViewer
+                                                x:Name="LeftNavScrollViewer"
                                                 TabNavigation="Once"
                                                 VerticalScrollBarVisibility="Auto">
                                                 <winui:ItemsRepeater