//This method is only called when Adding a Class.
 //DataSetConnector should already exist; if not, it is created and
 //the DataTables are loaded.
 public bool AddCourseRecord(CourseRecord cr)
 {
     if (XMLDataSetConnector.Instance.AddNewCourseRecordAndSTS(
         cr.GetStudent().GetID(), cr.GetSection().GetID(), Grade.None))
     {
         courseRecords.Add(cr);
         return true;
     }
     return false;
 }
        public bool ModifyCR(CourseRecord cr, String g)
        {
            String expression = "StudentID = '" + cr.GetStudent().GetID() + "' AND ";
            expression += "SectionID = '" + cr.GetSection().GetID() + "'";

            DataRow[] rows = _studentRecords.CRsAndSsToSs.Select(expression);
            if (rows.Length == 0) return false;

            StudentRecordsDataSet.CRsAndSsToSsRow r = (StudentRecordsDataSet.CRsAndSsToSsRow)rows[0];
            if (r.Grade.Equals(g)) return false;

            r.Grade = g;

            UpdateXml();
            return true;
        }
 //This method is only called when Dropping a Class.
 //DataSetConnector should already exist; if not, it is created and
 //the DataTables are loaded.
 public bool RemoveCourseRecord(CourseRecord cr)
 {
     if (XMLDataSetConnector.Instance.RemoveCourseRecordAndSTS(
          cr.GetStudent().GetID(), cr.GetSection().GetID()))
     {
         courseRecords.Remove(cr);
         return true;
     }
     return false;
 }