Binding to a DependencyProperty from a ControlTemplate

Question

I have a UserControl with a DependencyProperty called "MyObject." In UserControl.Resources I have a ControlTemplate with a Rectangle and I'm wanting to change the Fill based on a Property in MyObject using DataTriggers.

I'm just not sure how to bind to MyObject from within the ControlTemplate. Any ideas?

Here's some example code. Look for the "Not sure how to bind to the UserControl's DependencyProperty here" comment...

<UserControl.Resources>
    <ControlTemplate x:Key="SliderThumbVerticalDefault" TargetType="{x:Type Thumb">
        <Rectangle Height="5">
            <Rectangle.Style>
                <Style TargetType="{x:Type Rectangle}">
                    <Setter Property="Fill" Value"Gray" />

                    <Style.Triggers>
                        <DataTrigger Binding="{Binding Path=MyObject.IsOn}" Value="True"> <!-- Not sure how to bind to the UserControl's DependencyProperty here -->
                            <Setter Property="Fill" Value="Red" />
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </Rectangle.Style>
        </Rectangle>
    </ControlTemplate>
</UserControl.Resources>

Answer 1

Hi,

Welcome to our Microsoft Q&A platform!

You can try my code:

   <Style.Triggers>
                                    <DataTrigger Binding="{Binding RelativeSource={RelativeSource AncestorType=local:MyUserControl},Path=IsOn}"  Value="True">
                                        <!-- Not sure how to bind to the UserControl's DependencyProperty here -->
                                        <Setter Property="Fill" Value="Red" />
                                    </DataTrigger>
                                </Style.Triggers>

Thanks.