c# - 使用 MVVM 的 TreeView BringIntoView

Question

我希望用户能够在 TreeView 中搜索项目。输入搜索文本后，TreeViewItem 应滚动到 View 中。

现在我正在为 TreeView、TreeViewItems 和 MainView 使用 MVVM 模式。

我需要做什么才能使用 MVVM 获得 BringIntoView 的功能？有一些我可以绑定(bind)的属性(property)吗？ (在 MFC 中有类似 FirstVisibileItem 的东西)

已看到具有行为的“解决方案”。真的有必要吗？

Answer 1

根据提到的代码项目文章，这里是代码示例，展示了如何设置行为以及如何在 XAML 中集成行为。

设置行为:

/// <summary>
/// Exposes attached behaviors that can be
/// applied to TreeViewItem objects.
/// </summary>
public static class TreeViewItemBehavior
{
    #region IsBroughtIntoViewWhenSelected
    public static bool GetIsBroughtIntoViewWhenSelected(TreeViewItem treeViewItem)
    {
        return (bool)treeViewItem.GetValue(IsBroughtIntoViewWhenSelectedProperty);
    }

    public static void SetIsBroughtIntoViewWhenSelected(      TreeViewItem treeViewItem, bool value)
   {
       treeViewItem.SetValue(IsBroughtIntoViewWhenSelectedProperty, value);
   }

   public static readonly DependencyProperty IsBroughtIntoViewWhenSelectedProperty =
    DependencyProperty.RegisterAttached(
    "IsBroughtIntoViewWhenSelected",
    typeof(bool),
    typeof(TreeViewItemBehavior),
    new UIPropertyMetadata(false, OnIsBroughtIntoViewWhenSelectedChanged));

    static void OnIsBroughtIntoViewWhenSelectedChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
    {
        TreeViewItem item = depObj as TreeViewItem;
        if (item == null)
           return;

        if (e.NewValue is bool == false)
           return;

        if ((bool)e.NewValue)
           item.Selected += OnTreeViewItemSelected;
        else
           item.Selected -= OnTreeViewItemSelected;
    }

    static void OnTreeViewItemSelected(object sender, RoutedEventArgs e)
    {
       // Only react to the Selected event raised by the TreeViewItem
       // whose IsSelected property was modified. Ignore all ancestors
       // who are merely reporting that a descendant's Selected fired.
       if (!Object.ReferenceEquals(sender, e.OriginalSource))
         return;

       TreeViewItem item = e.OriginalSource as TreeViewItem;
       if (item != null)
          item.BringIntoView();
    }

    #endregion // IsBroughtIntoViewWhenSelected
}

然后在 XAML 中集成 TreeViewItemBehavior:

<TreeView.ItemContainerStyle>
  <Style TargetType="{x:Type TreeViewItem}">
    <Setter Property="local:TreeViewItemBehavior.IsBroughtIntoViewWhenSelected" Value="True"/>
  </Style>
</TreeView.ItemContainerStyle>

玩得开心:-)