Extracting elements from IEnumerable <ObservableCollection <T>> C #

Question

I have:

IEnumerable<ObservableCollection<PointCollection>> rings = from graphic in e.FeatureSet select ((Polygon)e.FeatureSet.Features).Rings; 

I want to extract all PointCollection from each graphic and combine them into one ObservableCollection. Something like that:

 ObservableCollection<PointCollection> allRings = ?; 

Is there a better way to repeat this without doing a bunch of nested ForEach statements?

Answer 1

You can use SelectMany :

 var allRings = new ObservableCollection<PointCollection>( rings.SelectMany(rings => rings) );