WpfToolkit AutoCompleteBox ContextMenu not working

Question

In one of my WPF project, I have integrated WPF Toolkit's AutoCompleteBox control. I need a custom Context Menu for this control and I have added one using the ContextMenu property. Unfortunately its not showing the custom created one but showing the default one (i.e. Cut, Copy, Paste with Cut & Copy as disabled).

To recreate the issue, I have created a sample project and the window contains 2 controls inside a Grid.

<Grid>
        <Grid.RowDefinitions>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
        </Grid.RowDefinitions>
        <toolkit:AutoCompleteBox>
            <toolkit:AutoCompleteBox.ContextMenu>
                <ContextMenu>
                    <MenuItem Header="Menu Item 1"></MenuItem>
                    <MenuItem Header="Menu Item 2"></MenuItem>
                </ContextMenu>
            </toolkit:AutoCompleteBox.ContextMenu>
        </toolkit:AutoCompleteBox>
        <TextBox Grid.Row="1" >
            <TextBox.ContextMenu>
                <ContextMenu>
                    <MenuItem Header="Menu Item 1"></MenuItem>
                    <MenuItem Header="Menu Item 2"></MenuItem>
                </ContextMenu>
            </TextBox.ContextMenu>
        </TextBox>
    </Grid>

The two controls have the same ContextMenu and if I run the solution, I can see that the custom created ContextMenu is working for TextBox and not for AutoCompleteBox.

Also, I set the same Context Menu to Grid (parent control) and set ContextMenu="{x:Null}" to TextBox & AutoCompleteBox. Now the ContextMenu is inherited for TextBox but not for AutoCompleteBox.

So my question is, how can I create a custom ContextMenu for AutoCompleteBox? If it is not by design(AutoCompleteBox), how can I add a ContextMenu to a custom AutoCompleteBox control which is inherited from AutoCompleteBox. Please advice.

Answer 1

AutoCompleteBox exposes dependency property TextBoxStyle which you can set to customize TextBox hosted inside AutoCompleteBox.

Another approach would be to provide your own template which i would strongly oppose since this DP is provide explicitly for the purpose you want i.e. to customize textBox from outside.

Create a style for TextBox with your custom ContextMenu and apply that template both on your TextBox and AutoCompleteBox. This sample is working fine -

<Grid>
   <Grid.Resources>
      <Style x:Key="CustomStyle" TargetType="TextBox"
             BasedOn="{StaticResource {x:Type TextBox}}">
         <Setter Property="ContextMenu">
             <Setter.Value>
                <ContextMenu>
                    <MenuItem Header="Header1"/>
                    <MenuItem Header="Header2"/>
                 </ContextMenu>
             </Setter.Value>
         </Setter>
      </Style>
   </Grid.Resources>
   <Grid.RowDefinitions>
      <RowDefinition/>
      <RowDefinition/>
   </Grid.RowDefinitions>
   <toolkit:AutoCompleteBox TextBoxStyle="{StaticResource CustomStyle}"/>
   <TextBox Grid.Row="1" Style="{StaticResource CustomStyle}"/>
</Grid>