[W] Setting CurrentPage in CarouselPage ctor works

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla39458.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla39458.cs
new file mode 100644 (file)
index 0000000..f24344e
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla39458.cs
@@ -0,0 +1,84 @@
+using System;
+
+using Xamarin.Forms.CustomAttributes;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls
+{
+       [Preserve(AllMembers = true)]
+       [Issue(IssueTracker.Bugzilla, 39458, "[UWP/WinRT] Cannot Set CarouselPage.CurrentPage Inside Constructor", PlatformAffected.WinRT)]
+       public class Bugzilla39458 : TestCarouselPage
+       {
+               public class ChildPage : ContentPage
+               {
+                       public ChildPage(int pageNumber)
+                       {
+                               var layout = new StackLayout();
+                               var MyLabel = new Label {
+                                       VerticalOptions = LayoutOptions.Center,
+                                       HorizontalOptions = LayoutOptions.Center,
+                                       FontSize = 21,
+                                       TextColor = Color.White,
+                                       Text = $"This is page {pageNumber}"
+                               };
+                               var TestBtn = new Button {
+                                       Text = "Go to Page 2",
+                                       IsEnabled = false,
+                                       BackgroundColor = Color.White
+                               };
+
+                               if (pageNumber != 2)
+                               {
+                                       TestBtn.IsEnabled = true;
+                                       TestBtn.Clicked += TestBtn_Clicked;
+                               }
+
+                               layout.Children.Add(MyLabel);
+                               layout.Children.Add(TestBtn);
+                               Content = layout;
+                       }
+
+                       private void TestBtn_Clicked(object sender, EventArgs e)
+                       {
+                               var carousel = Application.Current.MainPage as CarouselPage;
+                               carousel.CurrentPage = carousel.Children[1];
+                       }
+               }
+
+               public class DesiredPage : ChildPage
+               {
+                       public DesiredPage(int pageNumber) : base(pageNumber)
+                       {
+                       }
+               }
+
+               protected override void Init()
+               {
+                       var firstPage = new ChildPage(1);
+                       firstPage.BackgroundColor = Color.Blue;
+                       Children.Add(firstPage);
+
+                       var secondPage = new DesiredPage(2);
+                       secondPage.BackgroundColor = Color.Red;
+                       Children.Add(secondPage);
+
+                       var thirdPage = new ChildPage(3);
+                       thirdPage.BackgroundColor = Color.Green;
+                       Children.Add(thirdPage);
+
+                       CurrentPage = secondPage;
+               }
+
+#if UITEST
+               [Test]
+               public void Bugzilla39458Test()
+               {
+                       RunningApp.WaitForElement(q => q.Marked("This is page 2"));
+               }
+#endif
+       }
+}

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
index 1937653..65ec549 100644 (file)
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
@@ -133,6 +133,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla39499.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla39668.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla39829.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla39458.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla39853.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)_Template.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue1028.cs" />

diff --git a/Xamarin.Forms.Platform.WinRT/CarouselPageRenderer.cs b/Xamarin.Forms.Platform.WinRT/CarouselPageRenderer.cs
index 8b5e52b..97733cf 100644 (file)
--- a/Xamarin.Forms.Platform.WinRT/CarouselPageRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/CarouselPageRenderer.cs
@@ -92,8 +92,12 @@ namespace Xamarin.Forms.Platform.WinRT
 
                                _tracker.Element = newPage;
 
+                               // Adding Items triggers the SelectionChanged event,
+                               // which will reset the CurrentPage unless we tell it to ignore.
+                               _fromUpdate = true;
                                for (var i = 0; i < newPage.Children.Count; i++)
                                        Items.Add(newPage.Children[i]);
+                               _fromUpdate = false;
 
                                ((INotifyCollectionChanged)newPage.Children).CollectionChanged += OnChildrenChanged;
                                newPage.PropertyChanged += OnElementPropertyChanged;