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Hello,

I have a listbox with elements and a contextmenu on it.
But I want to display some MenuItems only if there are > 1 items selected in the ListBox.

My code is currently this:

<ListBox x:Name="lsbChampionsInGroup" Margin="10,220,5,11" SelectionMode="Multiple" HorizontalAlignment="Left" Width="160" RenderTransformOrigin="0.5,0.5">
            <ListBox.ItemContainerStyle>
                <Style TargetType="{x:Type ListBoxItem}">
                    <EventSetter Event="PreviewMouseRightButtonDown" Handler="OnListBoxItemPreviewMouseRightButtonDown" />
                </Style>
            </ListBox.ItemContainerStyle>

            <ListBox.ContextMenu>
                <ContextMenu Name="cmChampionsInGroup">
                    <MenuItem Header="Unselect all" Click="UnselectAllChampions" />
                    <Separator Background="CornflowerBlue" />
                    <MenuItem Header="Remove" Click="btnRemoveChampionsFromCurrentGroup_Click"/>
                    <Separator Background="CornflowerBlue" />
                    <MenuItem Header="Copy" Click="CopySelectedChampionsInCurrentGroup" />
                    <MenuItem Header="Paste" Click="PasteSelectedChampions" />
                </ContextMenu>
            </ListBox.ContextMenu>
        </ListBox>
</pre>


The ItemContainerStyle makes sure I do not unselect an item if a user right-clicks on it.

I would have to do this for 3 ListBoxes.

Sincerly
Bert
Posted

1 solution

You can handle the event System.Windows.Controls.ContextMenu.ContextMenuOpening:
http://msdn.microsoft.com/en-us/library/system.windows.frameworkelement.contextmenuopening%28v=vs.110%29.aspx[^].

In the handler of this event, check up your condition and adjust the visibility of the menu items in question:
http://msdn.microsoft.com/en-us/library/system.windows.uielement.isvisible(v=vs.110).aspx[^].

In other cases, this event handler is the point where you can modify the content of the context menu itself (its items): add/remove menu items, change their appearance, enable/disable status (http://msdn.microsoft.com/en-us/library/system.windows.uielement.isenabled(v=vs.110).aspx[^]), and so on, depending on the status of the context: the application or the UI element owning the context menu.

—SA
   

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