Question

ViewModelA:

inside its constructor (breakpoint hits the foll. line):

Messenger.Default.Register<int>(this, "token", OnHitIt);

ViewModelB:

breakpoint does hit this line:

Messenger.Default.Send(hitItId, "token")

But for some reason breakpoint never hits OnHitIt method, what could be the reason…

Answer 1

Try using

On ViewModelA:

Messenger.Default.Register<NotificationMessage<int>>(this, OnHitIt);

And the OnHitIt method would be-

private void OnHitIt(NotificationMessage<int> m)
{
    if (m.Notification == "token")
    {
        // code goes here
        // m.Content will get the int passed in
    }
}

On ViewModelB:

Messenger.Default.Send(new NotificationMessage<int>(hitItId, "token"));