Click here to Skip to main content
Click here to Skip to main content

WPF: Context Menu on List Item

By , 12 May 2010
Rate this:
Please Sign up or sign in to vote.

I am using WPF and MVVM. I have a Window and a view model attached to it via Datacontext. The window has a listbox, and its items have context menu. I am using DelegateCommand in my view model, and I want to bind a menu items in the context menu to this command.

The first problem is that by default the menu item is bound to the DataContext of the list box item, which may or may not have knowledge of the whole view model.

The second problem is that context menu is not part of the visual tree, so referring to the main window via FindAncestor or ElementName=... will not work.

You can get to the object immediately containing the context menu via the PlacementTarget property, but then you will need an ancestor of this object (“window”), and there is no built-in way to find an ancestor of a property.

An (almost) working solution that I found on the Internet after hours of search was to store the data context some property of the PlacementTarget – they used Tag for this purpose.

The “almost” part lies in the fact that if your command has CanExecute() method, the command parameter passed to it is sometimes null (see here).

<Window Name="MainWindow" ...>
    <Grid>
        <ListBox ItemsSource="{Binding Items}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal"
                               Tag="{Binding DataContext, ElementName=MainWindow}">
			...
                        <StackPanel.ContextMenu>
                             <MenuItem Header="do it"
    Command="{Binding PlacementTarget.Tag.MyCommand, 
	RelativeSource={RelativeSource AncestorType=ContextMenu}}"
    CommandParameter="{Binding}">
                        </StackPanel.ContextMenu>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>

License

This article, along with any associated source code and files, is licensed under The Apache License, Version 2.0

About the Author

Ivan Krivyakov
Technical Lead Thomson Reuters
United States United States
Ivan is a hands-on software architect/technical lead working for Thomson Reuters in the New York City area. At present I am mostly building complex multi-threaded WPF application for the financial sector, but I am also interested in cloud computing, web development, mobile development, etc.
 
Please visit my web site: www.ikriv.com.

Comments and Discussions

 
-- There are no messages in this forum --
| Advertise | Privacy | Mobile
Web02 | 2.8.140415.2 | Last Updated 12 May 2010
Article Copyright 2010 by Ivan Krivyakov
Everything else Copyright © CodeProject, 1999-2014
Terms of Use
Layout: fixed | fluid