Question

[code]

private static IOrderedEnumerable<Film> OrderBy(this IEnumerable<Film> source, Func<Film, object> order, bool desc)
{
    if (desc) { return source.OrderByDescending(order); }
    return source.OrderBy(order);
}

[Situation]

Ofcourse, linq already implements a order by. I’m only trying to generize it more. Mostly just to learn things, it doesn’t really add things other then that I can order by normally or order by descending with the same property.

[Question]

However I wish to make it more generic. Currently it only takes IEnumerable<T> and return IOrderedEnumerable<T> (where T currently is a movie. Custom model).
Is there any general type of list, enumerable or something that covers all List, IEnumerable IOrderedEnumerable etcetc?

Answer 1

Yes, there is. It’s IEnumerable<T>.

Classes like List<T> implement the IEnumerable<T> interface, so a method that takes IEnumerable<T> can be used with most any collection.

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You forgot to specify the generic parameter to the method: OrderBy<Film>.

The original OrderBy method also have a generic parameter for the type of the key. You might also want to use that, to make sure that the comparisons work properly, and that it doesn’t do a lot of unnecessary boxing and unboxing:

private static IOrderedEnumerable<Film> OrderBy<Film, Key>(this IEnumerable<Film> source, Func<Film, Key> order, bool desc) {
  if (desc) { return source.OrderByDescending(order); }
  return source.OrderBy(order);
}