private void PopulateDropDownLists()
{
using (var context = new SchoolEntities())
{
var allCourses = context.GetCourses().ToList();
var instructorID = Convert.ToInt32(InstructorsDropDownList.SelectedValue);
var instructor = (from p in context.People.Include("Courses")
where p.PersonID == instructorID
select p).First();
var assignedCourses = instructor.Courses.AsEnumerable();
var unassignedCourses = allCourses.Except(assignedCourses.AsEnumerable()).ToList();
UnassignedCoursesDropDownList.DataSource = unassignedCourses;
UnassignedCoursesDropDownList.DataBind();
UnassignedCoursesDropDownList.Visible = true;
AssignedCoursesDropDownList.DataSource = assignedCourses;
AssignedCoursesDropDownList.DataBind();
AssignedCoursesDropDownList.Visible = true;
}
}