Force context menu to recreate child controls each time it opens

contextmenu, data-binding, wpf

Solution

I was able to quickly do this by creating a `Style` for the `ContextMenu` that sets its `DataContext` to `null` when it is hidden. This will cause the `Binding`s to re-run when it is opened, as they will have a new source. If you set the `DataContext` explicitly for the `ContextMenu`, you'll have to move that to a setter:

<ContextMenu>
    <ContextMenu.Style>
        <Style TargetType="{x:Type ContextMenu}">
            <Style.Triggers>
                <Trigger Property="IsOpen" Value="False">
                    <Setter Property="DataContext" Value="{x:Null}" />
                </Trigger>
            </Style.Triggers>
        </Style>
    </ContextMenu.Style>
    <MenuItem Header="{Binding Color, Mode=OneTime}" />
</ContextMenu>

Problem

I have a context menu which contains a both a OneTime, one way binding and a second, non-OneTime two way binding to the same property. The goal is to have a color editor which displays the initial color value, and allows the user to change the selected value while still being able to compare it to the original. This works well the first time the context menu is opened, but the menu doesn't seem to fully recreate itself each time it is opened (cached?). Instead, it "remembers" the original binding value, instead of doing another OneTime binding from the source to get the new "initial" value. Is there a way to force a context menu to fully recreate its contents each time it is opened?

Original source