Question

This is a complete Newbie question and I understand but how do I transfer these two distinct Enumerable collections to a single ObservableCollections?

  var distinctLine1 = (from z in list
                            orderby z.ItemLine1
                            select z.ItemLine1).Distinct();
        var distinctLine2 = (from z in list
                            orderby z.ItemLine2
                            select z.ItemLine2).Distinct();
        foreach (var item in distinctLine1)
        {

        }

Sorry did change ObservableCollectionsList to ObservableCollections

ItemLine1 and ItemLine2 are both strings

Answer 1

I suppose you could probabl also call Distinct on union to exclude possible duplicates.

var union = distinctLine1.Union(distinctLine2).Distinct();

Or just

var union = distinctLine1.Union(distinctLine2);

And then simply create the target collection with ObservableCollection Constructor (IEnumerable):

var result = new ObservableCollection<string>(union);