c# only add unique items to list code example
Example 1: how to get unique list in c#
using(var dataModel = new DataModel())
{
var classes = dataModel.Attributes.Where(a => a.Field == "Class").Select(a => a.Key).Distinct().ToList();
}
Example 2: c# list with only unique items
If your requirements are to have no duplicates, you should be using a HashSet.
HashSet.Add will return false when the item already exists (if that even matters to you).