How to communicate from view model to view in MVVM in WPF

Question

I want to execute certain code in view if something happens in view model . I have looked into Prism event aggregator but I havent got success with prism 5. If there is more easier method to do so it will be helpful.Any blog or same code regarding this will also work

Please have a look that entry: http://stackoverflow.com/questions/15439841/mvvm-in-wpf-how-to-alert-viewmodel-of-changes-in-model-or-should-i?rq=1 — Ugur, Apr 29 '16 at 11:41
INotifyPropertyChanged is the way to go. Or regular events. In the view, add a DataContextChanged handler. When you get the datacontext, cast it to your viewmodel type and add handlers for PropertyChanged or whatever. — 15ee8f99-57ff-4f92-890c-b56153, Apr 29 '16 at 11:45

score 2 · Accepted Answer · answered Apr 29 '16 at 12:00

As Ed Plunkett says, the thing to do is listen for DataContextChanged in your view, as this is how View's are connected to ViewModels.

Here's an example:

public partial class MyView : UserControl
{
    public MyView ()
    {
        DataContextChanged += MyView_DataContextChanged;
    }

    private void MyView_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
    {
        //new ViewModel has been set.
        MyViewModel myViewModel = e.NewValue as MyViewModel;
        if (myViewModel != null)
        {
            //check for property changes
            myViewModel.PropertyChanged += MyViewModel_PropertyChanged;

            //custom event for specific update
            myViewModel.MyCustomEventTriggered += MyViewModel_MyCustomEventTriggered
        }
    }

    private void MyViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        //do your logic
    }

    private void MyViewModel_MyCustomEventTriggered(object sender, MyCustomEventArgs e)
    {
        //do your logic
    }
}

How to communicate from view model to view in MVVM in WPF

1 Answers1