How to change the color/opacity of the triangular icon on a TreeViewItem?
Asked Answered
A

1

6

Some of my TreeViewItems are clickable and some are not.

For those that are not clickable, I changed the Foreground color to gray.

However, if that item has children, I want to also change the little triangular bullet to gray.

How can I do that, something like this:

//PSEUDO-CODE:
<TreeViewItem IconBulletEnabled="False" IconBulletColor="#aaa" Header="Part 1"/>

alt text

Aristotelianism answered 14/10, 2009 at 15:57 Comment(0)
C
6

You will have to edit the ControlTemplate. I extracted the default one for you with Expression Blend. You need to muck around with it until you achieve the effect you want and then apply it to your TreeViewItems like this:

  <TreeViewItem Header="Word 1" ItemContainerStyle="{DynamicResource TreeViewItemStyle1}"/>

Here is the style itself:

        <Style x:Key="TreeViewItemFocusVisual">
            <Setter Property="Control.Template">
                <Setter.Value>
                    <ControlTemplate>
                        <Rectangle/>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <PathGeometry x:Key="TreeArrow" Figures="M0,0 L0,6 L6,0 z"/>
        <Style x:Key="ExpandCollapseToggleStyle" 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 Width="16" Height="16" Background="Transparent" Padding="5,5,5,5">
                            <Path x:Name="ExpandPath" Fill="Transparent" Stroke="#FF989898" Data="{StaticResource TreeArrow}">
                                <Path.RenderTransform>
                                    <RotateTransform Angle="135" CenterX="3" CenterY="3"/>
                                </Path.RenderTransform>
                            </Path>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter Property="Stroke" TargetName="ExpandPath" Value="#FF1BBBFA"/>
                                <Setter Property="Fill" TargetName="ExpandPath" Value="Transparent"/>
                            </Trigger>
                            <Trigger Property="IsChecked" Value="True">
                                <Setter Property="RenderTransform" TargetName="ExpandPath">
                                    <Setter.Value>
                                        <RotateTransform Angle="180" CenterX="3" CenterY="3"/>
                                    </Setter.Value>
                                </Setter>
                                <Setter Property="Fill" TargetName="ExpandPath" Value="#FF595959"/>
                                <Setter Property="Stroke" TargetName="ExpandPath" Value="#FF262626"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <Style x:Key="TreeViewItemStyle1" TargetType="{x:Type TreeViewItem}">
            <Setter Property="Background" Value="Transparent"/>
            <Setter Property="HorizontalContentAlignment" Value="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
            <Setter Property="VerticalContentAlignment" Value="{Binding VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
            <Setter Property="Padding" Value="1,0,0,0"/>
            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
            <Setter Property="FocusVisualStyle" Value="{StaticResource TreeViewItemFocusVisual}"/>
            <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" Style="{StaticResource ExpandCollapseToggleStyle}" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}"/>
                            <Border x:Name="Bd" SnapsToDevicePixels="true" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Column="1">
                                <ContentPresenter x:Name="PART_Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" ContentSource="Header"/>
                            </Border>
                            <ItemsPresenter x:Name="ItemsHost" Grid.Column="1" Grid.ColumnSpan="2" 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.ControlBrushKey}}"/>
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
                            </MultiTrigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
            <Style.Triggers>
                <Trigger Property="VirtualizingStackPanel.IsVirtualizing" Value="true">
                    <Setter Property="ItemsPanel">
                        <Setter.Value>
                            <ItemsPanelTemplate>
                                <VirtualizingStackPanel/>
                            </ItemsPanelTemplate>
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
Cessionary answered 14/10, 2009 at 16:6 Comment(1)
I know this is an old answer but I'm also trying to change the triangular icon colour. I've tried the code in this answer but it seems to have no effect on my tree view items (confirmed by changing all colours to "Red" with no visible change from the default).Netta

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