public static DataTable Filter(int?Session, int BranchID, int?LevelID, int?ClassID, int?GroupID)
 {
     try
     {
         return(SPs.SpEnrolledStudents(Session, BranchID, LevelID, ClassID, GroupID).GetDataSet().Tables[0]);
     }
     catch {
         return(null);
     }
 }