Dynamic Comparers - StephenCleary/Comparers GitHub Wiki
Sometimes you need to define a comparer at run-time; for example, applying a user-selected multi-column sort. The comparer extension methods work on any type of comparer, so you can construct a comparer starting from the Null comparer like this:
var compareColumns = new[] { "LastName", "FirstName" };
IComparer<Person> comparer = Compare<Person>.Null();
foreach (var column in compareColumns)
{
var localColumn = column;
Func<Person, string> selector = p => p.GetType().GetProperty(localColumn).GetValue(p, null) as string;
comparer = comparer.ThenBy(selector);
}
Equality comparers also support a Null comparer.