/// <summary>
 /// Returns specific candidate based on unique category/sno combination.
 /// Returns null if no match
 /// </summary>
 /// <param name="candidateCategory"></param>
 /// <param name="Sno"></param>
 /// <returns></returns>
 public static Candidate GetCandidateByCategoryAndSno(CandidateCategoryNo candidateCategory, CandidateSNo Sno)
 {
     return(Candidates.Where(c => c.S_no == Sno && c.Category_no == candidateCategory).FirstOrDefault());
 }
 /// <summary>
 /// Returns all candidates for a specified category
 /// </summary>
 /// <param name="candidateCategory"></param>
 /// <returns></returns>
 public static List <Candidate> GetCandidatesByCategory(CandidateCategoryNo candidateCategory)
 {
     return(Candidates.Where(c => c.Category_no == candidateCategory).ToList());
 }