using System.ComponentModel.Composition; using System.Windows; using System.Windows.Controls; using MediaAssistant.Controls.WaitScreen; using MefBasic; using MefBasic.Threading; using MediaAssistant.DAL; namespace MediaAssistant.Controls.MovieThumbnails { [Export] public partial class MovieThumbnailsView : IView { public MovieThumbnailsView() { InitializeComponent(); } private void HandleScrollChanged(object sender, ScrollChangedEventArgs e) { ShowVisibleItems(sender); } private void ShowVisibleItems(object sender) { var scrollViewer = (FrameworkElement) sender; var visibleAreaEntered = false; var visibleAreaLeft = false; var invisibleItemDisplayed = 0; foreach (Movie item in thumbnailListBox.Items) { if (item.IsVisible) continue; var listBoxItem = (FrameworkElement) thumbnailListBox.ItemContainerGenerator.ContainerFromItem(item); if (visibleAreaLeft==false && IsFullyOrPartiallyVisible(listBoxItem, scrollViewer)) { visibleAreaEntered = true; } else if (visibleAreaEntered) { visibleAreaLeft = true; } if(visibleAreaEntered) { if(visibleAreaLeft && ++invisibleItemDisplayed>10) break; var job = new Job(MakeVisible); job.Store.Add(item); job.Start(); } } } private static void MakeVisible(Job obj) { obj.Store.GetObject<Movie>().IsVisible = true; } protected bool IsFullyOrPartiallyVisible(FrameworkElement child, FrameworkElement scrollViewer) { var childTransform = child.TransformToAncestor(scrollViewer); var childRectangle = childTransform.TransformBounds(new Rect(new Point(0, 0), child.RenderSize)); var ownerRectangle = new Rect(new Point(0, 0), scrollViewer.RenderSize); return ownerRectangle.IntersectsWith(childRectangle); } } }
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