我找到了答案。我需要使用
myListBoxItem.BringIntoView();
问题是我不想添加任何代码隐藏,因为我正在实现 MVVM。
解决方案是使用Attached Behaviors。Josh Smith 有一篇很棒的文章:WPF 中的附加行为简介。
我在 ListBox 中的项目样式中添加了一个 Setter:
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter
Property="custom:ListBoxItemBehavior.IsBroughtIntoViewWhenSelected"
Value="True" />
</Style>
</ListBox.ItemContainerStyle>
并添加了以下类(仅将 Josh 的文章中的 TreeView 更改为 ListBox):
public static class ListBoxItemBehavior
{
#region IsBroughtIntoViewWhenSelected
public static bool GetIsBroughtIntoViewWhenSelected(ListBoxItem listBoxItem)
{
return (bool)listBoxItem.GetValue(IsBroughtIntoViewWhenSelectedProperty);
}
public static void SetIsBroughtIntoViewWhenSelected(
ListBoxItem listBoxItem, bool value)
{
listBoxItem.SetValue(IsBroughtIntoViewWhenSelectedProperty, value);
}
public static readonly DependencyProperty IsBroughtIntoViewWhenSelectedProperty =
DependencyProperty.RegisterAttached(
"IsBroughtIntoViewWhenSelected",
typeof(bool),
typeof(ListBoxItemBehavior),
new UIPropertyMetadata(false, OnIsBroughtIntoViewWhenSelectedChanged));
static void OnIsBroughtIntoViewWhenSelectedChanged(
DependencyObject depObj, DependencyPropertyChangedEventArgs e)
{
ListBoxItem item = depObj as ListBoxItem;
if (item == null)
return;
if (e.NewValue is bool == false)
return;
if ((bool)e.NewValue)
item.Selected += OnListBoxItemSelected;
else
item.Selected -= OnListBoxItemSelected;
}
static void OnListBoxItemSelected(object sender, RoutedEventArgs e)
{
// Only react to the Selected event raised by the ListBoxItem
// 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;
ListBoxItem item = e.OriginalSource as ListBoxItem;
if (item != null)
item.BringIntoView();
}
#endregion // IsBroughtIntoViewWhenSelected
}
有用!!