我正在合并在互联网上找到的两个例子。一个约stretched selection styles,一个约multi-selection in a treeview。
除了树视图的缩进外,我还能正常工作。我可以提供所有代码,但这不会解决它。
我的问题在于以下方法:
public static class TreeViewItemExtensions
{
public static int GetDepth(this TreeViewItem item)
{
FrameworkElement elem = item;
while (elem.Parent != null)
{
var tvi = elem.Parent as TreeViewItem;
if (tvi != null)
return tvi.GetDepth() + 1;
elem = elem.Parent as FrameworkElement;
}
return 0;
}
}
此方法尝试检索树中treeviewItem的深度。问题是:elem.Parent
总是 null 。这导致深度为0。
我认为这种情况正在发生,因为我使用的是HierarchicalDataTemplate
。我的xaml的一部分看起来像这样。
<TreeView Name="folderTree"
ItemsSource="{Binding Folders}"
SelectedItemChanged="folderTree_SelectedItemChanged"
HorizontalContentAlignment="Stretch">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Folders}"
DataType="{x:Type Model:IFolder}">
<StackPanel Orientation="Horizontal">
<StackPanel.Style>
<Style TargetType="{x:Type StackPanel}">
<Style.Triggers>
<DataTrigger Binding="{Binding IsSelected}"
Value="True">
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
</DataTrigger>
</Style.Triggers>
</Style>
</StackPanel.Style>
<Image Source="{Binding Converter={StaticResource iconConverter}}" Height="{Binding ElementName=theFile,Path=ActualHeight}"/>
<TextBlock Text="{Binding FileName}" Name="theFile"/>
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
我的树形视图的XAML如下所示:
<Style x:Key="{x:Type TreeViewItem}" TargetType="{x:Type TreeViewItem}">
<!-- leaving some stuff out here -->
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TreeViewItem}">
<ControlTemplate.Resources>
<local:LeftMarginMultiplierConverter Length="19" x:Key="lengthConverter" />
</ControlTemplate.Resources>
<StackPanel>
<!-- The upper part of the TreeViewItem -->
<Border Name="Bd"
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Padding="{TemplateBinding Padding}">
<!-- The margin is what we try to measure, how can we get the parents from the templatedParents? -->
<Grid Margin="{Binding Converter={StaticResource lengthConverter},
RelativeSource={RelativeSource TemplatedParent},
Path=.}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="19" />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<ToggleButton x:Name="Expander"
Style="{StaticResource ExpandCollapseToggleStyle}"
IsChecked="{Binding Path=IsExpanded,
RelativeSource={RelativeSource TemplatedParent}}"
ClickMode="Press"/>
<ContentPresenter x:Name="PART_Header"
Grid.Column="1"
ContentSource="Header"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
</Grid>
</Border>
<!-- the children of the TreeViewItem -->
<ItemsPresenter x:Name="ItemsHost" />
</StackPanel>
<!-- leaving some stuff out here with triggers -->
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
如何让HierarchicalDataTemplate填充
Parent
属性?
答案 0 :(得分:7)
我会扫描视觉树。
这是一个简单(甚至不那么优雅)的解决方案:
public static class TreeViewItemExtensions
{
public static int GetDepth(this TreeViewItem item)
{
DependencyObject target = item;
var depth = 0;
while (target != null)
{
if (target is TreeView)
return depth;
if (target is TreeViewItem)
depth++;
target = VisualTreeHelper.GetParent(target);
}
return 0;
}
}
干杯。