Passing origin of ContextMenu into WPF Command

mvvm, wpf, xaml

Solution

You'll need to use `TranslatePoint` to translate the top-left (0, 0) of the `ContextMenu` to a coordinate in the containing grid. You could do so by binding the `CommandParameter` to the `ContextMenu` and use a converter:

CommandParameter="{Binding IsOpen, ElementName=_menu, Converter={StaticResource PointConverter}}"

Another approach would be an attached behavior that automatically updates an attached readonly property of type `Point` whenever the `ContextMenu` is opened. Usage would look something like this:

<ContextMenu x:Name="_menu" local:TrackBehavior.TrackOpenLocation="True">
    <MenuItem Command="..." CommandParameter="{Binding Path=(local:TrackBehavior.OpenLocation), ElementName=_menu}"/>
</ContextMenu>

So the `TrackOpenLocation` attached property does the work of attaching to the `ContextMenu` and updating a second attached property (`OpenLocation`) whenever the `ContextMenu` is opened. Then the `MenuItem` can just bind to `OpenLocation` to get the location at which the `ContextMenu` was last opened.

Problem

Interesting problem related to firing commands from context menu items... I want to fire a command to insert a row in my control, InsertRowCmd. This command needs to know where to insert the row. I could use Mouse.GetPosition(), but that would get me the position of the mouse currently, which would be over the menu item. I want to get the origin of the context menu instead. Does any one have any suggestions on how to pass the origin of the context menu as a parameter to the command? Sample code: ``` <UserControl x:Name="MyControl"> <!--...--> <ContextMenu x:Name="menu"> <MenuItem Header="Insert Row" Command="{x:Static customCommands:MyCommands.InsertRowCmd}" CommandParameter="?"/> </ContextMenu> </UserControl> ``` My current ideas are as follows: -Use click handler instead so that I can find the origin in code. The problem is that I would then have to handle enabling/disabling. -Handle click event and save the origin of the context menu. Pass this saved information into the command. I have verified that click events fire before the command is executed. Any ideas? EDIT: I'm using Josh Smith's CommandSinkBinding to route the command handling into my ViewModel class. So the code that handles the command execution knows nothing about the view.

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