Removing Selection Indicator from TreeView on Windows

Environment

Product	Version	Author
TreeView for .NET MAUI	7.1.0	Dobrinka Yordanova

Description

When using a RadTreeView in a .NET MAUI application on Windows, the default behavior includes a selection indicator on items that are selected. This article demonstrates how to remove the selection indicator from TreeView by updating the control template.

This KB article also answers the following questions:

• How can I customize the appearance of selected items in RadTreeView on Windows?
• What steps are needed to modify the control template of TreeView?
• How do I apply a custom style to TreeView in .NET MAUI?

Solution

To remove the selection indicator from RadTreeView on Windows, follow these steps:

1. Define a new ControlTemplate that omits the selection indicator and other undesired visual elements.
2. Create a Style for TreeViewItemView that applies this ControlTemplate.
3. Apply the Style either implicitly within the ResourceDictionary or explicitly through the TreeViewDescriptor.ItemStyle property.

Using Implicit Style

Add the following XAML to your .NET MAUI page to apply the style implicitly:

<ContentPage.Resources>
    <ResourceDictionary>
        <ControlTemplate x:Key="TreeViewItemView_ControlTemplate_WinUI">
            <telerik:RadBorder BackgroundColor="{TemplateBinding BackgroundColor}"
                               BorderColor="{TemplateBinding BorderColor}"
                               BorderBrush="{TemplateBinding BorderBrush}"
                               BorderThickness="{TemplateBinding BorderThickness}"
                               CornerRadius="{TemplateBinding CornerRadius}">
                <Grid>
                    <telerik:TreeViewItemLayout Indentation="{TemplateBinding Indentation}"
                                                Spacing="{TemplateBinding Spacing}"
                                                Padding="{TemplateBinding ContentPadding}">
                        <ContentPresenter />
                    </telerik:TreeViewItemLayout>
                    <!-- this is the selected indicaotr that is displayed on winui when selection is made -->

                    <!--<telerik:RadBorder IsVisible="{TemplateBinding IsSelected}"
                                        BackgroundColor="{x:Static telerikCore:CoreTelerikStyles.AccentColor}"
                                        HorizontalOptions="Start"
                                        CornerRadius="2"
                                        WidthRequest="3"
                                        ScaleY="0.6" />-->
                </Grid>
            </telerik:RadBorder>
        </ControlTemplate>

        <Style TargetType="telerik:TreeViewItemView">
            <Setter Property="ControlTemplate" Value="{StaticResource TreeViewItemView_ControlTemplate_WinUI}"/>
        </Style>
    </ResourceDictionary>
</ContentPage.Resources>
<telerik:RadTreeView x:Name="treeView"
                     AutomationId="treeView"
                     ItemsSource="{Binding Items}">
    <telerik:TreeViewDescriptor DisplayMemberPath="Name"
                                ItemsSourcePath="Children"
                                TargetType="{x:Type local:Item}" />
    <telerik:RadTreeView.BindingContext>
        <local:ViewModel/>
    </telerik:RadTreeView.BindingContext>
</telerik:RadTreeView>

Using Explicit Style

To use an explicit style, set the above-defined style to the TreeViewDescriptor.ItemStyle property. Refer to the TreeView item style documentation for more details on using explicit styles.