C#: Difference between List and Collection (CA1002, Do not expose generic lists) [duplicate]

by

In short, the generic list does not have virtual methods for Add, Remove etc, as it was designed to be fast, not extensible. This means that you cannot swap this concrete implementation out for a useful subclass (even though you can subclass it as it is not sealed).

Therefore, by exposing the List itself, you can never extend your collection to track add or remove operations (for example) without breaking the public contract of the class.

By exposing your collection as an IList or some-such, you can still use the List as the actual backing-store, but you retain future extensibility as you can swap out the concerete implementation later without changing the public contract of your class.

More Related Contents:

  1. Convert List to List
  2. Select N random elements from a List in C#
  3. What’s the best way of implementing a thread-safe Dictionary?
  4. ObservableCollection that also monitors changes on the elements in collection
  5. Collection was modified; enumeration operation may not execute in ArrayList [duplicate]
  6. Properties vs. Fields: Need help grasping the uses of Properties over Fields
  7. How to check if IEnumerable is null or empty?
  8. How to easily initialize a list of Tuples?
  9. What .NET collection provides the fastest search
  10. Thread-safe List property
  11. The opposite of Intersect()
  12. How do I override List’s Add method in C#?
  13. Multi Value Dictionary?
  14. C# Sortable collection which allows duplicate keys
  15. Why do C# collection initializers work this way?
  16. How to hide public methods from IntelliSense
  17. Does the Enumerator of a Dictionary return key value pairs in the order they were added?
  18. Enum to Dictionary in C#
  19. What is ‘1 in Collection type Name
  20. Initial capacity of collection types, e.g. Dictionary, List
  21. Enum to Dictionary in C#
  22. Case-INsensitive Dictionary with string key-type in C#
  23. System.InvalidOperationException: Collection was modified
  24. Returning ‘IList’ vs ‘ICollection’ vs ‘Collection’
  25. C# – Get the item type for a generic list
  26. Getters and Setters are bad OO design? [duplicate]
  27. How add or remove object while iterating Collection in C#
  28. How should I use properties when dealing with read-only List members
  29. How to hide some members of an interface
  30. readonly keyword does not make a List ReadOnly?

Leave a Comment