Hashtable(IHashCodeProvider hcp,IComparer comparer) Message: Please use Hashtable(IEqualityComparer) instead. old: public Skills(IHashCodeProvider codeProvider, IComparer comparer) { innerHash = new Hashtable(codeProvider, comparer); } ========================================================================================== new: public Skills(IHashCodeProvider codeProvider, IEqualityComparer comparer) { innerHash = new Hashtable(codeProvider, comparer); }