我正在使用TreeView控件,当其中一个TreeViewItem被点击时,它会自动滚动到左对齐。我已经查看了我的样式和控件模板,但没有找到任何相关内容。是否有默认的控件模板导致此行为?我想禁用它。
public class NoScrollTreeView : TreeView
{
public class NoScrollTreeViewItem : TreeViewItem
{
public NoScrollTreeViewItem() : base()
{
this.RequestBringIntoView += delegate (object sender, RequestBringIntoViewEventArgs e) {
e.Handled = true;
};
}
protected override DependencyObject GetContainerForItemOverride()
{
return new NoScrollTreeViewItem();
}
}
protected override DependencyObject GetContainerForItemOverride()
{
return new NoScrollTreeViewItem();
}
}
在花费数小时解决这个问题后,我找到了适合自己的解决方案。
Brian提供的解决方案可以防止TreeViewItem上的RequestBringIntoView事件冒泡,但不幸的是,如果您通过编程方式更改选定的项目,则也会阻止TreeViewItem的显示:
yourtreeview.SelectedItem = yourtreeviewitem
<Style x:Key="{x:Type TreeView}" TargetType="TreeView">
<Setter Property="OverridesDefaultStyle" Value="True" />
<Setter Property="SnapsToDevicePixels" Value="True" />
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
<Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TreeView">
<Border Name="Border" BorderThickness="0" Padding="0" Margin="1">
<ScrollViewer Focusable="False" CanContentScroll="False" Padding="0">
<Components:AutoScrollPreventer Margin="0">
<ItemsPresenter/>
</Components:AutoScrollPreventer>
</ScrollViewer>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
using System;
using System.Windows;
using System.Windows.Controls;
namespace LiveContext.Designer.GUI.Components {
public class AutoScrollPreventer : StackPanel
{
public AutoScrollPreventer() {
this.RequestBringIntoView += delegate(object sender, RequestBringIntoViewEventArgs e)
{
// stop this event from bubbling so that a scrollviewer doesn't try to BringIntoView..
e.Handled = true;
};
}
}
希望这对你有所帮助。
好的,我最终能够像这样获取默认样式:
using (Stream sw = File.Open(@"C:\TreeViewDefaults.xaml", FileMode.Truncate, FileAccess.Write))
{
Style ts = Application.Current.FindResource(typeof(TreeView)) as Style;
if (ts != null)
XamlWriter.Save(ts, sw);
}
<Style TargetType="TreeView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:s="clr-namespace:System;assembly=mscorlib"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Style.Triggers>
<Trigger Property="VirtualizingStackPanel.IsVirtualizing">
<Setter Property="ItemsControl.ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate><VirtualizingStackPanel IsItemsHost="True" /></ItemsPanelTemplate>
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
</Style.Triggers>
<Style.Resources>
<ResourceDictionary />
</Style.Resources>
<Setter Property="Panel.Background">
<Setter.Value><DynamicResource ResourceKey="{x:Static SystemColors.WindowBrushKey}" /></Setter.Value>
</Setter>
<Setter Property="Border.BorderBrush">
<Setter.Value><SolidColorBrush>#FF828790</SolidColorBrush></Setter.Value>
</Setter>
<Setter Property="Border.BorderThickness">
<Setter.Value><Thickness>1,1,1,1</Thickness></Setter.Value>
</Setter>
<Setter Property="Control.Padding">
<Setter.Value><Thickness>1,1,1,1</Thickness></Setter.Value>
</Setter>
<Setter Property="TextElement.Foreground">
<Setter.Value><DynamicResource ResourceKey="{x:Static SystemColors.ControlTextBrushKey}" /></Setter.Value>
</Setter>
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility">
<Setter.Value><x:Static Member="ScrollBarVisibility.Auto" /></Setter.Value>
</Setter>
<Setter Property="ScrollViewer.VerticalScrollBarVisibility">
<Setter.Value><x:Static Member="ScrollBarVisibility.Auto" /></Setter.Value>
</Setter>
<Setter Property="Control.VerticalContentAlignment">
<Setter.Value><x:Static Member="VerticalAlignment.Center" /></Setter.Value>
</Setter>
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="TreeView">
<Border BorderThickness="{TemplateBinding Border.BorderThickness}"
BorderBrush="{TemplateBinding Border.BorderBrush}"
Name="Bd" SnapsToDevicePixels="True">
<ScrollViewer CanContentScroll="False"
HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
Background="{TemplateBinding Panel.Background}"
Padding="{TemplateBinding Control.Padding}"
Name="_tv_scrollviewer_"
SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}"
Focusable="False">
<ItemsPresenter />
</ScrollViewer>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="UIElement.IsEnabled">
<Setter Property="Panel.Background" TargetName="Bd">
<Setter.Value>
<DynamicResource ResourceKey="{x:Static SystemColors.ControlBrushKey}" />
</Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>False</s:Boolean>
</Trigger.Value>
</Trigger>
<Trigger Property="VirtualizingStackPanel.IsVirtualizing">
<Setter Property="ScrollViewer.CanContentScroll" TargetName="_tv_scrollviewer_">
<Setter.Value><s:Boolean>True</s:Boolean></Setter.Value>
</Setter>
<Trigger.Value>
<s:Boolean>True</s:Boolean>
</Trigger.Value>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
很不幸,它看起来并不有用。我没有在那里看到任何属性来停止自动滚动焦点的事情。
仍在寻找中...
看起来我在MSDN上找到了一个好线索:
听起来这是与滚动视图和焦点系统的交互。
当元素在ScrollViewer(它是TreeView模板的一部分)中被聚焦时,ScrollViewer会被指示使该元素可见。它会自动响应并滚动到所请求的元素。
处理这些焦点请求的ScrollViewer内部方法都是私有的和/或内部的,因此您无法访问它们。我认为在这种情况下你不能做太多事情;这就是焦点的工作方式。
那么,就这样了吗?肯定有一种方法可以修改TreeView模板,使ScrollViewer不具有这种行为...