Should I always return IEnumerable instead of IList?

Question

When I\'m writing my DAL or other code that returns a set of items, should I always make my return statement:

public IEnumerable GetRecentItems         


        

Answer 1

TL; DR; – summary

• If you develop in-house software, do use the specific type(Like List) for the return values and the most generic type for input parameters even in case of collections.
• If a method is a part of a redistributable library’s public API, use interfaces instead of concrete collection types to introduce both return values and input parameters.
• If a method returns a read-only collection, show that by using IReadOnlyList or IReadOnlyCollection as the return value type.

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