You are trying to sort a Generic List of Objects based on a property of the Objects.
There are two easy options for sorting a Generic List populated with Objects: in place and sorting to a new List. Use Linq.
“In Place” sorting of an existing List (the code below only works with text fields):
using System.Linq; Users.Sort((a, b) => string.Compare(a.LastName, b.LastName));
Sort a List to a new list:
List<Users> UserList = Users.OrderBy(o => o.LastName).ToList();