在WPF MVVM中对子按钮登录事件启用父窗口菜单

Question

I have a scenario, I am having a MainWindow.xaml. This window has menus (which are initially disabled) and user controls. On one of the user control I have a login button clicking which Login pop up window open up. After successful login I want to Enable my main window disabled menu items. How can I achieve this functionality in WPF MVVM?

Answer 1

Are you using any kind of MVVM Framework?

If so.

Most of them have some kind o event service. For example Caliburn.Micro has EventAggregator.

I would call such event in child view model and subscribe to it in parent one. In your scenario it would be something like that (in Caliburn.Micro):

class ChildViewModel
{
    ...
    public void HandleLogin()
    {
        ...
        _eventAggregator.Publish(new LoginEventArgs);
    }
}

class ParentViewModel : IHandle<LoginEventArgs>
{
    public void Handle(LoginEventArgs args)
    {
        ..
    }
}

With the use of such event service you achieve separation of your ViewModels and you much flexibility because you can handle such LoginEvents in other view models in your application.

As mentioned before many MVVM frameworks has such service:

• Caliburn
• Prism
• MVVM Light

If not.

You can assembly your own event aggregator.
Here are some sources which can be helpful in such homebrew implementation:

• SO
• MSDN