Gets the number of keys in the dictionary. This property must be overridden in the derived class.

Returns a collection of all of the values in the dictionary associated with key, or changes the set of values associated with key. If the key is not present in the dictionary, an ICollection enumerating no values is returned. The returned collection of values is read-write, and can be used to modify the collection of values associated with the key.

Gets a read-only collection all the keys in this dictionary.

Gets a read-only collection of all key-value pairs in the dictionary. If a key has multiple values associated with it, then a key-value pair is present for each value associated with the key.

Gets a read-only collection of all the values in the dictionary.