CODEWITHSUNDEEP
wpfmvvmprism
DocGigawatts
DocGigawatts

Reputation: 285

Linking controls in separate views

I have two separate views each containing a ScrollViewer. I want to slave one to the other in terms of scrolling. (Views are being injected using PRISM)

I can do this trivially if they are in the same view. However I seem to be stuck doing it between isolated views. (The views are isolated for a good reason... well I think!)

What I think I want to do is echo the ScrollViewer 'ScrollChangedEvent' to the ViewModel layer then use some linking service to pass a message to the 2nd ViewModel.

However I'm struggling to work out how to drive the 2nd ScrollViewer from the ViewModel without violating MVVM.

Sure I'm missing something obvious so a shove in the right direction would be greatly appreciated.

Thanks

Upvotes: 0

Views: 74

Answers (1)

Eli Arbel
Eli Arbel

Reputation: 22739

There are several ways to go about this. One would be, as you suggested, to transfer the scroll change to the view model. From there you can use a loose pub/sub mechanism (such as Prism's Event Aggregator) or a shared object that is available to both view models to transmit the event from one view model to the other.

My recommendation would be to use Prism.

When the second view model receives the event, it can publish it to the view using another event the view can directly consume, or through a property (using an attached property you can bind to that calls ScrollViewer.ScrollToVerticalOffset)

Upvotes: 1

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