public void LoadEnrollCourseComboBox() //function to load the CourseID column values into the combobox. This function is called as soon as the EnrollForCourse Window is opened.
 {
     try
     {
         EnrollCourseComboBox.ItemsSource       = studentBL.GetCoursesAsList();
         EnrollCourseComboBox.SelectedValuePath = "CourseID";
         EnrollCourseComboBox.DisplayMemberPath = "Name";
     }
     catch (Exception ex)
     {
         MessageBox.Show(ex.Message, "Error", MessageBoxButton.OK, MessageBoxImage.Error);
     }
 }