Question

I’m writing a custom control for a program. The control has a ComboBox in its template, among other things. Something as simple as this works to reproduce:

 <Style TargetType="{x:Type local:CustomControl1}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:CustomControl1}">
                <Border Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}">
                    <ComboBox />
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

If I right-click on this control, the PreviewMouseRightButtonUp event is raised, but the MouseRightButtonUp event is not. I presume this is because the ComboBox control sets e.Handled to true in its own PreviewMouseRightButtonUp event, preventing the other event from being raised. I’m making that guess because if I swap a Rectangle for the ComboBox, I get both events, and if in my custom control I set e.Handled to true in the Preview event I only get the preview event.

The program I’m writing the control for expects both events to be raised when a right-click happens, and I doubt I’ll be able to get them to change this. Am I going to have to recreate the ComboBox in a way that doesn’t eat the preview event, or is there another trick?

Answer 1

You can actually receive handled events passing true in the UIElement.Addhandler call. If it is handled you can raise a new event?

AddHandler(PreviewMouseLeftButtonDownEvent, new MouseButtonEventHandler(OnMouseLeftButtonDow), true);

You can use snoop to see if and if so which element sets the e.Handled=true;