I have a WPF TreeView for which I have specified two HierarchicalDataTemplates, and I use a template selector to choose which one to apply based on a type in a data bound object. The hierarchical data templates get applied and I see the expected names of items in the TreeView.
However, when I try and set the ItemContainerStyle for tree view items then it looks like the hierarchical data templates are no longer applied: the label for each tree view item is set to the class name of the object that the item is bound to. The style I am applying sets Template to the TreeViewItem ControlTemplate (I have plans to modify this template slightly but for now I am using the unmodified one which I exported from Visual Studio).
Data template selector
public class NodeTypeTemplateSelector : DataTemplateSelector
{
public DataTemplate Type1Template { get; set; }
public DataTemplate Type2Template { get; set; }
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
if (item == null) return base.SelectTemplate(null, container);
var layer = item as LayersItemVM;
if (layer != null)
{
switch (layer.NodeType)
{
case NodeType.Type1:
return Type1Template;
case NodeType.Type2:
return Type2Template;
default:
return base.SelectTemplate(item, container);
}
}
return base.SelectTemplate(item, container);
}
}
Main Window XAML
<Window x:Class="TreeViewSimple2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:TreeViewSimple2"
mc:Ignorable="d"
Loaded="MainWindow_OnLoaded"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<HierarchicalDataTemplate x:Key="Type1Template">
<StackPanel>
<Label Content="{Binding Path=Name}"></Label>
</StackPanel>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate x:Key="Type2Template">
<StackPanel>
<Label Content="{Binding Path=Name}"></Label>
</StackPanel>
</HierarchicalDataTemplate>
<local:NodeTypeTemplateSelector Type1Template="{StaticResource Type1Template}" Type2Template="{StaticResource Type2Template}" x:Key="NodeTypeTemplateSelector" />
</Window.Resources>
<Grid>
<TreeView x:Name="TreeView" ItemTemplateSelector="{StaticResource NodeTypeTemplateSelector}">
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TreeViewItem}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition MinWidth="19" Width="Auto"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<ToggleButton x:Name="Expander" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}">
<ToggleButton.Style>
<Style TargetType="{x:Type ToggleButton}">
<Setter Property="Focusable" Value="False"/>
<Setter Property="Width" Value="16"/>
<Setter Property="Height" Value="16"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border Background="Transparent" Height="16" Padding="5" Width="16">
<Path x:Name="ExpandPath" Data="M0,0 L0,6 L6,0 z" Fill="Transparent" Stroke="#FF989898">
<Path.RenderTransform>
<RotateTransform Angle="135" CenterY="3" CenterX="3"/>
</Path.RenderTransform>
</Path>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsChecked" Value="True">
<Setter Property="RenderTransform" TargetName="ExpandPath">
<Setter.Value>
<RotateTransform Angle="180" CenterY="3" CenterX="3"/>
</Setter.Value>
</Setter>
<Setter Property="Fill" TargetName="ExpandPath" Value="#FF595959"/>
<Setter Property="Stroke" TargetName="ExpandPath" Value="#FF262626"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Stroke" TargetName="ExpandPath" Value="#FF1BBBFA"/>
<Setter Property="Fill" TargetName="ExpandPath" Value="Transparent"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsMouseOver" Value="True"/>
<Condition Property="IsChecked" Value="True"/>
</MultiTrigger.Conditions>
<Setter Property="Stroke" TargetName="ExpandPath" Value="#FF262626"/>
<Setter Property="Fill" TargetName="ExpandPath" Value="#FF595959"/>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Column="1" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="True">
<ContentPresenter x:Name="PART_Header" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" ContentStringFormat="{TemplateBinding HeaderStringFormat}" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Border>
<ItemsPresenter x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsExpanded" Value="False">
<Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed"/>
</Trigger>
<Trigger Property="HasItems" Value="False">
<Setter Property="Visibility" TargetName="Expander" Value="Hidden"/>
</Trigger>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsSelected" Value="True"/>
<Condition Property="IsSelectionActive" Value="False"/>
</MultiTrigger.Conditions>
<Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightBrushKey}}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}}"/>
</MultiTrigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</TreeView.ItemContainerStyle>
</TreeView>
</Grid>
Try this template:
<TreeView x:Name="TreeView" ItemTemplateSelector="{StaticResource NodeTypeTemplateSelector}">
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TreeViewItem}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition MinWidth="19" Width="Auto"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<ToggleButton x:Name="Expander" ClickMode="Press"
IsChecked="{Binding Path=IsExpanded, RelativeSource={RelativeSource TemplatedParent}}">
<ToggleButton.Style>
<Style TargetType="{x:Type ToggleButton}">
<Setter Property="Focusable" Value="False"/>
<Setter Property="Width" Value="16"/>
<Setter Property="Height" Value="16"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border Background="Transparent" Height="16" Padding="5" Width="16">
<Path x:Name="ExpandPath" Data="M0,0 L0,6 L6,0 z" Fill="Transparent" Stroke="#FF989898">
<Path.RenderTransform>
<RotateTransform Angle="135" CenterY="3" CenterX="3"/>
</Path.RenderTransform>
</Path>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsChecked" Value="True">
<Setter Property="RenderTransform" TargetName="ExpandPath">
<Setter.Value>
<RotateTransform Angle="180" CenterY="3" CenterX="3"/>
</Setter.Value>
</Setter>
<Setter Property="Fill" TargetName="ExpandPath" Value="#FF595959"/>
<Setter Property="Stroke" TargetName="ExpandPath" Value="#FF262626"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Stroke" TargetName="ExpandPath" Value="#FF1BBBFA"/>
<Setter Property="Fill" TargetName="ExpandPath" Value="Transparent"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsMouseOver" Value="True"/>
<Condition Property="IsChecked" Value="True"/>
</MultiTrigger.Conditions>
<Setter Property="Stroke" TargetName="ExpandPath" Value="#FF262626"/>
<Setter Property="Fill" TargetName="ExpandPath" Value="#FF595959"/>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<Border Name="Bd" Grid.Column="1" Background="{TemplateBinding Control.Background}"
BorderBrush="{TemplateBinding Control.BorderBrush}"
BorderThickness="{TemplateBinding Control.BorderThickness}"
Padding="{TemplateBinding Control.Padding}" SnapsToDevicePixels="true">
<ContentPresenter x:Name="PART_Header" ContentSource="Header"
HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}"/>
</Border>
<ItemsPresenter x:Name="ItemsHost" Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="TreeViewItem.IsExpanded" Value="false">
<Setter TargetName="ItemsHost" Property="UIElement.Visibility" Value="Collapsed"/>
</Trigger>
<Trigger Property="ItemsControl.HasItems" Value="false">
<Setter TargetName="Expander" Property="UIElement.Visibility" Value="Hidden"/>
</Trigger>
<Trigger Property="TreeViewItem.IsSelected" Value="true">
<Setter TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"
Property="Border.Background"/>
<Setter Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"
Property="Control.Foreground"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="TreeViewItem.IsSelected" Value="true"/>
<Condition Property="TreeViewItem.IsSelectionActive" Value="false"/>
</MultiTrigger.Conditions>
<Setter TargetName="Bd"
Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightBrushKey}}"
Property="Border.Background"/>
<Setter Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}}"
Property="Control.Foreground"/>
</MultiTrigger>
<Trigger Property="UIElement.IsEnabled" Value="false">
<Setter Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" Property="Control.Foreground"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="VirtualizingPanel.IsVirtualizing" Value="true">
<Setter Property="ItemsControl.ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<VirtualizingStackPanel/>
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</TreeView.ItemContainerStyle>
</TreeView>