The APIpassed the id column in a variable named surprisingly, 'id'
For example, if you wanted to goto a details page whenever you clicked on a row:
Or a full example
cs.Add(x => x.MemberID).SetAsPrimaryKey().SetHidden(true);
cs.Add(x => x.Rank);
cs.Add(x => x.LastName);
cs.Add(x => x.Initials);
In this case, the MemberID is passed as the 'id' variable in the function