standards-c-sharp
Choosing the correct type for an enumerable
Supported types
Only the following enumerable types may be returned from public methods:
IEnumerable<T>ISet<T>IList<T>IDictionary<K, V>IReadOnlyDictionary<K, V>KeyedCollection<T>byte[](special case for raw binary data)
Which one should I use?
The following chart shows how to decide which general collection type to use for your implementation, internal exposure and public API exposure:
Thread safety
The concrete types above can be have multiple readers, but are not thread-safe for mutations. Some have thread-safe analogs.
List<T>=>SynchronizedCollection<T>Dictionary<K,V>=>ConcurrentDictionary<K,V>HashSet<T>=> No direct analog. You could create your own.SortedSet<T>=> No direct analog. You could trySortedList.Synchronized(myUnsynchronizedSortedList).SortedDictionary<T>=> No direct analog. Write your own synchronized wrapper.KeyedCollection<T>=> No direct analog. Write your own synchronized wrapper.