Bind Command to MenuItem

Question

Hi

I have ListView and i am trying to bind command to ContextMenu of ListView.

<ListView x:Name="listView1" ItemsSource="{Binding Path=Persons}">
            <ListView.Resources>
                <ContextMenu x:Key="ItemContextMenu">
                    <MenuItem Header="Add" />
                    <MenuItem Header="Edit"/>
                    <Separator/>
                    <MenuItem Header="Delete" Command="{Binding Msg}" /> 
                </ContextMenu>
            </ListView.Resources>
            <ListView.ItemContainerStyle>
                <Style TargetType="ListViewItem">
                    <!--<EventSetter Event="PreviewMouseLeftButtonDown" />--><!--Handler="OnListViewItem_PreviewMouseLeftButtonDown" />-->
                    <Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}"/>
                    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
                </Style>
            </ListView.ItemContainerStyle>
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="Name" DisplayMemberBinding="{Binding Path=Name}" />
                    <GridViewColumn Header="Sur Name" DisplayMemberBinding="{Binding Path=SurName}" />
                    <GridViewColumn Header="Age" DisplayMemberBinding="{Binding Path=Age}" />
                </GridView>
            </ListView.View>


        </ListView>
        <Button Content="Message" Command="{Binding Msg}" />

Binding to Button works well but when i click to delete item in ContextMenu, command is not working! Why?

Answer 1

Your problem is related to using bindings in resources. They normally don't work unless you are using something like {Binding Path=Value,Source={x:Static Some.StaticProperty}}. In order for ElementName or DataContext bindings to work you need to resort to help of ElementSpy and DataContextSpy. In your particular case if you are relying on DataContext binding, your XAML should look like this:

        <ListView.Resources>
            <DataContextSpy x:Name="spy" />
            <ContextMenu x:Key="ItemContextMenu">
                <MenuItem Header="Add" />
                <MenuItem Header="Edit"/>
                <Separator/>
                <MenuItem Header="Delete" Command="{Binding DataContext.Msg,Source={StaticResource spy}}" /> 
            </ContextMenu>
        </ListView.Resources>