ReadOnlyDictionary<TKey, TValue>
public class ReadOnlyDictionary<TKey, TValue> : ICollection<KeyValuePair<TKey, TValue>>, IEnumerable<KeyValuePair<TKey, TValue>>, IEnumerable, IDictionary<TKey, TValue>, IReadOnlyCollection<KeyValuePair<TKey, TValue>>, IReadOnlyDictionary<TKey, TValue>, ICollection, IDictionary
public sealed class KeyCollection<TKey, TValue> : ICollection<TKey>, IEnumerable<TKey>, IEnumerable, IReadOnlyCollection<TKey>, ICollection
public sealed class ValueCollection<TKey, TValue> : ICollection<TValue>, IEnumerable<TValue>, IEnumerable, IReadOnlyCollection<TValue>, ICollection