Approach for binding on a MVVM application using Portable Class Libraries

Question

I'm trying to port the core of an application across to Portable Class Libraries and don't appear to have binding support.

I'm trying to bind a property on my ViewModel to my Model, which consists of an ObservableDictionary (INotifyPropertyChanged, INotifyCollectionChanged, IDictionary<string, string>). I do this usually (with WP7) by using the following code when initialising the view model:

SetBinding(MyProperty, new Binding(string.Format("MyDictionary[{0}]", "thekey")) { Source = MyModel });

How would I approach this when using Portable Class Libraries, where it seems like the Binding class is unavailable?

Answer 1

I've implemented this by having the base class for the ViewModels wire up to the PropertyChanged event of the ViewModel and the NotifyCollectionChanged event of the ObservableDictionary. I then have a method (with a set of overloads for additionally supplying an implementation of an IPclValueConverter which is a copy of the IValueConverter) which adds to a collection of PclBinding objects which is a set of PropertyInfo, dictionary key, IPclValueConverter and a converter parameter.

Within the PropertyChanged/NotifyCollectionChanged I check to see if the binding should be updated, and if so perform the update passing the value through a converter if present.

This means that from my original example, I now write the following inside my ViewModel which creates the binding as required:

SetBinding(() => MyProperty, "theKey");

If anyone is actually interested in this code I'd be happy to post it up. :)