MenuItem可见性绑定的ContextMenu

Question

I need to create a context menu for a menu item. Visibility of the context menu is binded to the ViewModel.

When the property change to true, using MVVM Light, the context menu appears in the UI even if there is no right click on the menu item. What can I do to hide the context menu when the value is false, and alllow it to be visible only on right click ?

private Boolean _IsEditable;
public Boolean IsEditable
{
    get { return _IsEditable; }
    set
    {
        if (_IsEditable == value) return;
        _IsEditable = value;
        RaisePropertyChanged("IsEditable");
    }
}

<Menu DockPanel.Dock="Top">
   <MenuItem Header="{Binding Menu.Business}" Visibility="{Binding allowUI, Converter={StaticResource BoolToVisConverter} }">
      <MenuItem.ContextMenu>
         <ContextMenu Visibility="{Binding Menu.IsEditable, Converter={StaticResource BoolToVisConverter} }">
            <MenuItem>
               <MenuItem.Header>
                  <TextBox Text="{Binding Menu.Business, UpdateSourceTrigger=PropertyChanged}" LostFocus="end_change_UI" />
               </MenuItem.Header>
            </MenuItem>

         </ContextMenu>
      </MenuItem.ContextMenu>
   </MenuItem>
</Menu>

Answer 1

You could apply a Style to the MenuItem that only sets the ContextMenu property when the IsEditable source property is set to true :

<Menu DockPanel.Dock="Top">
    <MenuItem Header="{Binding Menu.Business}" Visibility="{Binding allowUI, Converter={StaticResource BoolToVisConverter} }">
        <MenuItem.Style>
            <Style TargetType="MenuItem" BasedOn="{StaticResource {x:Type MenuItem}}">
                <Style.Triggers>
                    <DataTrigger Binding="{Binding Menu.IsEditable}" Value="True">
                        <Setter Property="ContextMenu">
                            <Setter.Value>
                                <ContextMenu>
                                    <MenuItem>
                                        <MenuItem.Header>
                                            <TextBox Text="{Binding Menu.Business, UpdateSourceTrigger=PropertyChanged}" LostFocus="end_change_UI" />
                                        </MenuItem.Header>
                                    </MenuItem>
                                </ContextMenu>
                            </Setter.Value>
                        </Setter>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </MenuItem.Style>
    </MenuItem>
</Menu>