Gets all the keys in the NameValueCollection.
Assembly: System (in System.dll)
If the collection is empty, this method returns an empty String array, not Nothing.
The arrays returned by are cached for better performance and are automatically refreshed when the collection changes. A derived class can invalidate the cached version by calling InvalidateCachedArrays, thereby forcing the arrays to be recreated.
This method is an O(n) operation, where n is Count.