/// <summary>
/// Gets all the departments and related courses.
/// </summary>
public List<Department> GetDepartments()
{
using (SchoolEntities context = new SchoolEntities())
{
// Use System.Data.Objects.ObjectQuery(T).Include to eagrly load the related courses.
return context.Departments.Include("Courses").OrderBy(d => d.Name).ToList();
}
}
/// <summary>
/// Updates department and its related courses.
/// </summary>
public void UpdateDepartment(Department updated)
{
using (SchoolEntities context =
new SchoolEntities())
{
try
{
// Perform validation on the updated order before applying the changes.
// The ApplyChanges method examines the change tracking information
// contained in the graph of self-tracking entities to infer the set of operations
// that need to be performed to reflect the changes in the database.
context.Departments.ApplyChanges(updated);
context.SaveChanges();
}
catch (UpdateException ex)
{
// To avoid propagating exception messages that contain sensitive data to the client tier,
// calls to ApplyChanges and SaveChanges should be wrapped in exception handling code.
throw new InvalidOperationException("Failed to update the department. Try your request again.");
}
}
}