Wie die Farbe / Opazität des dreieckigen Symbol auf TreeViewItem ändern?

Question

Einige meiner TreeViewItems sind klickbare und manche nicht.

Für diejenigen, die nicht anklickbar sind, Ich habe die Vordergrund Farbe grau.

Wenn jedoch das Element hat Kinder , ich möchte auch das kleine dreieckige ändern Kugel bis grau.

Wie kann ich das tun, so etwas wie folgt aus:

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

Answer 1

Sie müssen die Control bearbeiten. Ich extrahierte den Standard für Sie mit Expression Blend. Sie müssen damit vertrödeln, bis Sie den gewünschten Effekt erreichen und es dann wie folgt auf Ihre TreeViewItems gelten:

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

Hier ist der Stil selbst:

        <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>