我希望用户能够在TreeView中搜索项目。在输入搜索文本后,TreeViewItem应该滚动到视图中。
现在我正在使用MVVM模式的TreeView,为TreeViewItems和主视图。
我要做什么才能利用MVVM获得BringIntoView的功能?有什么属性可以绑定吗?(在MFC中有类似FirstVisibileItem的东西)
看到一个行为的"解决方案"。真的有必要吗?
根据前面提到的代码项目文章,下面是代码示例,展示了如何设置Behavior以及如何在XAML中集成Behavior。
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>
玩得开心点:-)
这个问题可以通过行为来解决。
这篇CodeProject文章非常好地描述了它,并且它开箱即用。