How to Cast from DictionaryCollection to IList

Hi--

How to cast given below dictionaryCollection to IList<Isomething> ?

public IList<ISomething> FetchAll(Object obj1, Object obj2)
{
   var dictCollection = Cache.GetAll(IsCacheMiss(obj1, obj2)),key).ToList();
   IList<ISomething> isomething = ???? How to cast here ???

}

//Implementation of GetAll method
public DictionaryCollection<Tid, Tvalue> GetAll(Func<IEnumerable<TValue>>IsCacheMiss, Func<TValue, TId> key)
{
  code...
  Code...
}