TreeView BringIntoView与MVVM

Question

我希望用户能够搜索TreeView中的项目。 输入搜索文本后，TreeViewItem应滚动到视图中。

现在我正在使用MVVM模式的TreeView，为TreeViewItems和MainView。

如何使用MVVM获得BringIntoView的功能我需要做些什么？ 有一些我可以绑定的属性吗？ （在MFC中有类似于FirstVisibileItem的东西）

已经看到了具有行为的“解决方案”。它真的有必要吗？

Answer 1

该问题可以通过行为来解决。

这个CodeProject article描述非常好，它开箱即用。

Answer 2

根据上述代码项目文章，以下是代码示例，演示如何设置行为以及如何将行为集成到XAML中。

设置的行为：

/// <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集成TreeViewItemBehavior：

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

玩得开心:-)