A pure Xaml solution for setting a property to a value when a button is clicked?

Question

Hi,

In my app, I'd like to make the context menu of a button appear when the user left clicks on the button. I can do this by creating an event handler for button's click event and then setting it's context menu's IsOpen property to true, but I'm wondering if there's a pure xaml solution to do the same thing. Any ideas?

Thanks!

Answer 1

I suppose you would have to use an event trigger on Button.Click. If it is then possible to use an element like

<Setter Property="ContextMenu.IsOpen" Value="True" />

you could be getting there.

Answer 2

You could make it appear by using an event trigger but you'd need another one to make it disappear. I can't think of any combination of existing properties that would get you anything useful though.

Answer 3

I would handle something like this through the view model class.

public Visibility ContextMenuVisibility
{
    get { return (this.ShowContextMenu) ? Visibility.Visible : Visibility.Collapsed; }
}

public bool ShowContextMenu { get; set; }

Handling those dynamic events that are halfway between the view and model is exactly what the view model layer is designed to do.

Oh, and I'm -1'ing myself for not being a pure XAML solution. Just offering up another alternative to a onCheckChanged event.

Answer 4

You can create a new template for the button and then provide a context menu in the template's visual tree. Something like this:

<Style TargetType="{x:Type Button}">
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="{x:Type Button}">
        <Border>
          <ContentPresenter HorizontalAlignment="Center"
                            VerticalAlignment="Center"/>
          <Border.ContextMenu>
            <ContextMenu Name="contextMenu">
              <MenuItem Header="Here's a menu."/>
            </ContextMenu>
          </Border.ContextMenu>
        </Border>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

You could then trigger using the IsPressed property of the button and hook it up using a setter with contextMenu as the TargetName.

My real question is, what are you using this for? Opening a context-menu on left-click is going to be inherently flawed, because context-menus, by their nature, close when any other element is clicked. Which means this trigger, even when properly set up, will simply open and close the context menu immediately. I am curious as to why you need this kind of behavior; perhaps there is a better way of doing it than using a context-menu.