C# List<> OrderBy Alphabetical Order

Question

I'm using C# on Framework 3.5. I'm looking to quickly sort a Generic List<>. For the sake of this example lets say I have a List of a Person type with a property of lastname. How would I sort this List using a lambda expression?

List<Person> people = PopulateList();
people.OrderBy(???? => ?????)

Answer 1

people.OrderBy(person => person.lastname).ToList();

Answer 2

Do you need the list to be sorted in place, or just an ordered sequence of the contents of the list? The latter is easier:

var peopleInOrder = people.OrderBy(person => person.LastName);

To sort in place, you'd need an IComparer<Person> or a Comparison<Person>. For that, you may wish to consider ProjectionComparer in MiscUtil.

(I know I keep bringing MiscUtil up - it just keeps being relevant...)

Answer 3

If you mean an in-place sort (i.e. the list is updated):

people.Sort((x, y) => string.Compare(x.LastName, y.LastName));

If you mean a new list:

var newList = people.OrderBy(x=>x.LastName).ToList(); // ToList optional