将命令绑定到MenuItem

Question

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>