How to compare 2 List objects to get the missing value from the List

Question

How do I use the \"NOT IN\" to get the missing data, to be added to \"foo\" List.

var accessories = new List(); 
var foo = new List()         


        

Answer 1

Use List.Except:

foo.AddRange(accessories.Except(foo));

From MSDN:

Except Produces the set difference of two sequences.