Comme évoqué précédemment, j’utilise actuellement ta classe “NavigationPresenter” pour réaliser des transitions entre view. Je suis parti pour cela du code fourni dans ta solution AnimatedContentPresenter.sln.

Tout fonctionne bien…

Sauf que quand je place un “breakpoint” sur le constructeur de Page1View, je m’aperçois que la vue est instanciée 2 fois au lancement de l’application… J’ai pas réussi à comprendre pourquoi . De même, lorsque que j’active l’animation de la “Page2″ (pour passer de la Page1 à la Page2), je m’aperçois que le constructeur de cette View est appelé 2 fois de suite; et que celui de la page1 est également appelé une fois …

De ton côté, tu as déjà constaté ce mode de fonctionnement bizarroïde ?

Fred

I checked your sample again and the Visual State of the GUI is lost changing the pages. According to this statement I am interested in an answer:

Jeremy Says:
April 9th, 2009 at 10:31 am
Hmmm I noticed this behaviour too. I’ll check it out as soon as I can to try to understand how to fix it…

Do you know now how to fix with your code the visual recreation ?

But I noticed this behaviour with Transitionals framework. Without using a transition between usercontrol the visual state is lost. With Transitionals I switch/fade between datatemplates and the entered data in a textbox is saved switching back… ???

Someone knows why?

Now, I had some time to look at the problem. I also learned some new things about Wpf in these months.

Anyway I created a new viewmodel and a small demonstration program. I thought you might be interested.

Here is the link to the blog post: http://reyntjes.blogspot.com/2009/07/viewmodel-for-fluidkit-transition.html

Actually, you’re not supposed to refer view related stuff (like controls) in the viewmodel classes. The viewmodel represents an abstraction of the view: one of the advantage of this is that you can unit test your viewmodel classes easily.

There are 2 ways controls can “talk” with viewmodel classes: through databinding and through command. Using databinding you can ensure that viewmodel properties and view controls are in sync. Using commands, you can react to a user interaction in your view (for example a click on a button – without using events). If you need to deal with ItemsControl (ListBox for example), you can use ICollectionView too.

Can anyone tell me how to refer controls which are in UI in View from ViewModel classes in MVVM Design Pattern for WPF.

Like if i have an WPF interface in View and want to write events in ViewModel, this i know how to do. But, when i need to refer the controls for example validation or etc. as we were earlier doing like “this.txtFirstName” in VS2.0, how can this be achievable in ViewModel class.