public IEnumerable<VivaClass> Vivas()
 {
     using (SqlConnection connection = new SqlConnection(new ConnectionString().GetConString(("SqlConString"))))
     {
         string query = "Select ID,GroupID,StudentName,ProjectName,City,Date,Time,isMake FROM SchedualTB";
         SqlCommand cmd = new SqlCommand(query, connection);
         connection.Open();
         using (SqlDataReader dr = cmd.ExecuteReader())
         {
             while (dr.Read())
             {
                 VivaClass obj = new VivaClass();
                 obj.ID = (int(dr["ID"];
                 obj.Student.GroupID = (string)dr["GroupID"];
                 obj.Student.StudentName = (string)dr["StudentName"];
                 obj.Student.ProjectName = (string)dr["ProjectName"];
                 obj.Student.City = (string)dr["City"];
                 obj.Date = (string)dr["Date"].ToString();
                 obj.Time = (string)dr["Time"];
                 obj.IsMake = (bool)dr["isMake"];
                 yield return obj;
             }
         }
     }
 }    
     public IEnumerable<VivaClass> VivaObj()
     {
         SqlConnection hookup = new SqlConnection(new ConnectionString().GetConString(("SqlConString")));
         string query = "Select ID,GroupID,StudentName,ProjectName,City,Date,Time,isMake FROM SchedualTB";
         SqlCommand cmd = new SqlCommand(query, hookup);
         hookup.Open();
         using (SqlDataReader dr = cmd.ExecuteReader())
         {
             while (dr.Read())
             {
                 VivaClass obj = new VivaClass();
                 obj.ID = Convert.ToInt32(dr["ID"]);
                 obj.StudentObJ.GroupID = Convert.ToString(dr["GroupID"]);
                 obj.StudentObJ.StudentName = Convert.ToString(dr["StudentName"]);
                 obj.StudentObJ.ProjectName = Convert.ToString(dr["ProjectName"]);
                 obj.StudentObJ.City = Convert.ToString(dr["City"]);
                 obj.Date = dr["Date"].ToString();
                 obj.Time = dr["Time"].ToString();
                 obj.IsMake = Convert.ToBoolean(dr["isMake"].ToString());
                 yield return obj;
             }
     }
 }