如何通过持有物品来重新排序itemcontrol中的物品？

Question

嗨，我尝试在ItemsControl中重新订购items。当我设置ItemsControl元素ManipulationMode到ManipulationModes.TranslateYScrollView dosent工作。对于这个问题，我在Holding事件中更改了ManipulationMode，但我遇到了一个新问题。 在我的代码中，我们需要释放手指后，再次触摸移动。我需要握住并移动手指拖动没有握住和释放的物品，然后再次触摸并移动。此版本对我和用户 不利，请帮帮我。

我的代码：

<ItemsControl ItemsSource="{Binding Items}" 
       x:Name="todoList"> 

      <ItemsControl.ItemTemplate> 
       <DataTemplate> 
        <Border Background="{Binding Path=color, Converter={StaticResource ColorToBrushConverter}}" 
       Height="75" 
       x:Name="todoItem"> 
         <i:Interaction.Behaviors> 
          <Behaviors:DragReOrderBehavior /> 
         </i:Interaction.Behaviors> 

         <Grid Background="{StaticResource itemGradient}"> 
          <!--task text--> 
          <TextBlock Text="{Binding Title}" 
         Margin="15,15,0,15" FontSize="25" TextWrapping="Wrap" 
         x:Name="taskText"/> 
         </Grid> 
        </Border> 
       </DataTemplate> 
      </ItemsControl.ItemTemplate> 
     </ItemsControl> 

和行为：

public class DragReOrderBehavior : DependencyObject, IBehavior 
{ 
    private static readonly int AutoScrollHitRegionSize = 80; 

    private DispatcherTimer _autoScrollTimer; 
    private FrameworkElement _dragItem; 
    private int _initialDragIndex; 
    private bool IsActive = false; 
    private ItemsControl itemscontrolList; 
    private ItemViewModel draggedItemVM; 
    private MainViewModel VM; 
    private ResettableObservableCollection<ItemViewModel> itemsListVm; 
    private ScrollViewer _scrollViewer; 
    // private SoundEffect _moveSound; 
    public DependencyObject AssociatedObject { get; private set; } 


    public void Attach(DependencyObject associatedObject) 
    { 
     AssociatedObject = associatedObject; 
     var fw = (FrameworkElement)AssociatedObject; 

     //fw.ManipulationMode = ManipulationModes.TranslateY | ManipulationModes.System; 
     ////fw.ManipulationStarted += fw_ManipulationStarted; 
     fw.Holding += fw_Holding; 
     //fw.ManipulationDelta += fw_ManipulationDelta; 
     //fw.ManipulationCompleted += fw_ManipulationCompleted; 
     if (fw.RenderTransform == null || fw.RenderTransform as TranslateTransform == null) 
     { 
      fw.RenderTransform = new TranslateTransform(); 
     } 
     // a timer which is used to periodically detect the position of the 
     // item being dragged in order to allow auto-scroll behaviour 
     _autoScrollTimer = new DispatcherTimer(); 
     _autoScrollTimer.Interval = TimeSpan.FromMilliseconds(50); 
     _autoScrollTimer.Tick += (s, e) => 
     { 
      AutoScrollList(); 
      ShuffleItemsOnDrag(); 
     }; 

     // _moveSound = SoundEffect.FromStream(TitleContainer.OpenStream("Sounds/Windows XP Menu Command.wav")); 
    } 

    void fw_Holding(object sender, HoldingRoutedEventArgs e) 
    { 
     //if (Math.Abs(e.Cumulative.Translation.Y) > Math.Abs(e.Cumulative.Translation.X)) 
     // { 
     //var fw = (FrameworkElement)AssociatedObject; 

     //fw.ManipulationMode = ManipulationModes.TranslateRailsY | ManipulationModes.System; 
      IsActive = true; 

      // locate the element being dragged 
      _dragItem = AssociatedObject as FrameworkElement; 
      itemscontrolList = AssociatedObject.Ancestors<ItemsControl>().OfType<ItemsControl>().FirstOrDefault(); 
      draggedItemVM = ((ItemViewModel)_dragItem.DataContext); 
      VM = (MainViewModel)itemscontrolList.DataContext; 
      itemsListVm = VM.Items; 
      _scrollViewer = itemscontrolList.Descendants<ScrollViewer>() 
           .Cast<ScrollViewer>() 
           .SingleOrDefault(); 
      _dragItem.SetVerticalOffset(0); 
      _dragItem.ManipulationMode = ManipulationModes.TranslateY; 
      _dragItem.ManipulationDelta += fw_ManipulationDelta; 
      _dragItem.ManipulationCompleted += fw_ManipulationCompleted; 
      _dragItem.UpdateLayout(); 
      itemscontrolList.UpdateLayout(); 

      _initialDragIndex = itemsListVm.IndexOf(draggedItemVM); 

      // fade out the items in the list, other than the dragged one 
      foreach (var item in itemscontrolList.GetItemsInView() 
              .Where(i => i.DataContext != draggedItemVM)) 
      { 
       item.Animate(1.0, 0.7, "Opacity", 300, 0); 
      } 

      _autoScrollTimer.Start(); 
     // } 
    } 

}

Answer 1

ListView控件& GridView控件支持重新排序项。思考如何使用它们？

首先，你可以通过设置CanDragItemsCanReorderItemsAllowDrop假，当你在你的ListView按住该项目，然后上面设置为true的属性，这将使重新排序功能，禁用此功能。