diff options
Diffstat (limited to 'Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs')
| -rw-r--r-- | Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs b/Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs new file mode 100644 index 00000000..3e1fd096 --- /dev/null +++ b/Xamarin.Forms.Platform.WinRT/CarouselViewRenderer.cs @@ -0,0 +1,220 @@ +using System; +using System.Collections.Specialized; +using System.ComponentModel; +using System.Linq; +using Windows.UI.Xaml; +using Windows.UI.Xaml.Controls; +using Windows.UI.Xaml.Media; +using WFlipView = Windows.UI.Xaml.Controls.FlipView; +using WBinding = Windows.UI.Xaml.Data.Binding; +using WApp = Windows.UI.Xaml.Application; +using WSize = Windows.Foundation.Size; +using WDataTemplate = Windows.UI.Xaml.DataTemplate; + +#if WINDOWS_UWP + +namespace Xamarin.Forms.Platform.UWP +#else + +namespace Xamarin.Forms.Platform.WinRT +#endif +{ + public class CarouselViewRenderer : ViewRenderer<CarouselView, FrameworkElement> + { + WFlipView _flipView; + + bool _leftAdd; + + ICarouselViewController Controller + { + get { return Element; } + } + + protected override void OnElementChanged(ElementChangedEventArgs<CarouselView> e) + { + base.OnElementChanged(e); + + if (e.OldElement != null) + { + _flipView.SelectionChanged -= SelectionChanged; + _flipView.ItemsSource = null; + Element.CollectionChanged -= CollectionChanged; + } + + if (e.NewElement != null) + { + if (_flipView == null) + { + _flipView = new FlipView { IsSynchronizedWithCurrentItem = false, ItemTemplate = (WDataTemplate)WApp.Current.Resources["ItemTemplate"] }; + } + + _flipView.ItemsSource = Element.ItemsSource; + _flipView.SelectedIndex = Element.Position; + _flipView.SelectionChanged += SelectionChanged; + Element.CollectionChanged += CollectionChanged; + } + + if (_flipView != Control) + SetNativeControl(_flipView); + } + + protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e) + { + if (e.PropertyName == "Position" && _flipView.SelectedIndex != Element.Position) + { + if (!_leftAdd) + _flipView.SelectedIndex = Element.Position; + _leftAdd = false; + } + + base.OnElementPropertyChanged(sender, e); + } + + void CollectionChanged(object sender, NotifyCollectionChangedEventArgs e) + { + Controller.SendSelectedPositionChanged(_flipView.SelectedIndex); + + switch (e.Action) + { + case NotifyCollectionChangedAction.Add: + if (e.NewStartingIndex <= Element.Position) + { + _leftAdd = true; + int position = Element.Position + e.NewItems.Count; + PositionChanged(position); + } + break; + + case NotifyCollectionChangedAction.Move: + break; + + case NotifyCollectionChangedAction.Remove: + if (Element.Count == 0) + throw new InvalidOperationException("CarouselView must retain a least one item."); + + if (e.OldStartingIndex < Element.Position) + PositionChanged(Element.Position - e.OldItems.Count); + break; + + case NotifyCollectionChangedAction.Replace: + break; + + case NotifyCollectionChangedAction.Reset: + break; + + default: + throw new Exception($"Enum value '{(int)e.Action}' is not a member of NotifyCollectionChangedAction enumeration."); + } + } + + void PositionChanged(int position) + { + if (!_leftAdd) + _flipView.SelectedIndex = position; + Element.Position = position; + Controller.SendSelectedPositionChanged(position); + } + + void SelectionChanged(object sender, SelectionChangedEventArgs e) + { + object[] addedItems = e.AddedItems.ToArray(); + object[] removedItems = e.RemovedItems.ToArray(); + + object addedItem = addedItems.SingleOrDefault(); + if (addedItem != null) + { + PositionChanged(_flipView.SelectedIndex); + Controller.SendSelectedItemChanged(addedItems.Single()); + } + } + } + + public class ItemControl : ContentControl + { + CarouselView _carouselView; + object _item; + View _view; + + public ItemControl() + { + DataContextChanged += OnDataContextChanged; + } + + CarouselView CarouselView => LoadCarouselView(); + + IItemViewController Controller => CarouselView; + + protected override WSize ArrangeOverride(WSize finalSize) + { + _view.Layout(new Rectangle(0, 0, CarouselView.Width, CarouselView.Height)); + return base.ArrangeOverride(finalSize); + } + + protected override WSize MeasureOverride(WSize availableSize) + { + LoadCarouselView(); + + if (_item != null) + { + SetDataContext(_item); + _item = null; + } + + return base.MeasureOverride(availableSize); + } + + CarouselView LoadCarouselView() + { + if (_carouselView != null) + return _carouselView; + + DependencyObject parent = VisualTreeHelper.GetParent(this); + CarouselViewRenderer renderer = default(CarouselViewRenderer); + + do + { + if (parent == null) + return null; + + renderer = parent as CarouselViewRenderer; + if (renderer != null) + break; + + parent = VisualTreeHelper.GetParent(parent); + } while (true); + + _carouselView = renderer.Element; + return _carouselView; + } + + void OnDataContextChanged(FrameworkElement sender, DataContextChangedEventArgs args) + { + object item = args.NewValue; + + if (_carouselView != null) + SetDataContext(item); + + else if (item != null) + _item = item; + } + + void SetDataContext(object item) + { + // type item + object type = Controller.GetItemType(item); + + // activate item + _view = Controller.CreateView(type); + _view.Parent = CarouselView; + _view.Layout(new Rectangle(0, 0, CarouselView.Width, CarouselView.Height)); + + // render item + IVisualElementRenderer renderer = Platform.CreateRenderer(_view); + Platform.SetRenderer(_view, renderer); + Content = renderer; + + // bind item + Controller.BindView(_view, item); + } + } +}
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