TreeView BringIntoView與MVVM

Question

我希望用戶能夠搜索TreeView中的項目。 輸入搜索文本後，TreeViewItem應滾動到視圖中。

現在我正在使用MVVM模式的TreeView，爲TreeViewItems和MainView。

如何使用MVVM獲得BringIntoView的功能我需要做些什麼？ 有一些我可以綁定的屬性嗎？ （在MFC中有類似於FirstVisibileItem的東西）

已經看到了具有行爲的「解決方案」。它真的有必要嗎？

Answer 1

該問題可以通過行爲來解決。

這個CodeProject article描述非常好，它開箱即用。

Answer 2

根據上述代碼項目文章，以下是代碼示例，演示如何設置行爲以及如何將行爲集成到XAML中。

設置的行爲：

/// <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 
} 

然後在XAML集成TreeViewItemBehavior：

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

玩得開心:-)