Fixes 7992 Changes UWP DatePicker to show the picker flyout on DatePickerFocus() (#8056)

* Setup test page

* initial DatePickerRenderer Changes

* wip

* Open Flyout on OnElementFocusChangeRequested

* Update to handle when picker not visible

Co-authored-by: Rui Marinho <[email protected]>
Fixes #7992

Author: 2 people

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue7992.cs

@@ -0,0 +1,49 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 7992, "Datepicker is not opened when we call Datepicker.Focus() in UWP", PlatformAffected.UWP)]
+
+	public class Issue7992 : TestContentPage
+	{
+		protected override void Init()
+		{
+			var stackLayout = new StackLayout();
+			Content = stackLayout;
+
+			stackLayout.Children.Add(new Label
+			{
+				Text = "Label to keep picker from getting initial focus"
+			});
+
+			var datePicker = new DatePicker();
+			stackLayout.Children.Add(datePicker);
+
+			var buttonFocus = new Button
+			{
+				Text = "Calls Focus() on the date picker, which should open a date picker flyout."
+			};
+			buttonFocus.Clicked += (s, e) =>
+			{
+				datePicker.IsVisible = true;
+				datePicker.Focus();
+			};
+			stackLayout.Children.Add(buttonFocus);
+
+			var buttonNotVisible = new Button
+			{
+				Text = "Makes the picker not visible and calls Focus(), which should open a full screen picker flyout."
+			};
+			buttonNotVisible.Clicked += (s, e) =>
+			{
+				datePicker.IsVisible = false;
+				datePicker.Focus();
+			};
+			stackLayout.Children.Add(buttonNotVisible);
+
+		}
+
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -113,6 +113,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue7593.xaml.cs">
       <SubType>Code</SubType>
     </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Issue7992.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue7792.xaml.cs">
       <SubType>Code</SubType>
     </Compile>
@@ -1762,4 +1763,4 @@
       <Generator>MSBuild:Compile</Generator>
     </EmbeddedResource>
   </ItemGroup>
-</Project>
+</Project>

Xamarin.Forms.Platform.UAP/DatePickerRenderer.cs

@@ -4,6 +4,7 @@
 using Windows.UI.Text;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Controls.Primitives;
 using Windows.UI.Xaml.Documents;
 using Windows.UI.Xaml.Media;
 using Xamarin.Forms.Internals;
@@ -65,6 +66,18 @@ void ControlOnLoaded(object sender, RoutedEventArgs routedEventArgs)
 			UpdateTextColor();
 		}
 
+		internal override void OnElementFocusChangeRequested(object sender, VisualElement.FocusRequestArgs args)
+		{
+			base.OnElementFocusChangeRequested(sender, args);
+
+			// Show a picker fly out on focus to match iOS and Android behavior
+			var flyout = new DatePickerFlyout { Placement = FlyoutPlacementMode.Bottom, Date = Control.Date };
+			flyout.DatePicked += (p, e) => Control.Date = p.Date;
+			if (!Element.IsVisible)
+				flyout.Placement = FlyoutPlacementMode.Full;
+			flyout.ShowAt(Control);
+		}
+
 		void WireUpFormsVsm()
 		{
 			if (!Element.UseFormsVsm())