static void AddNewDepartmentAndCourses(int departmentID, int courseID)
{
using (var service = new Service1Client())
{
Department newDepartment = new Department()
{
DepartmentID = departmentID,
Budget = 13000.000m,
Name = "New Department",
StartDate = DateTime.Now
};
OnlineCourse newCourse = new OnlineCourse()
{
CourseID = courseID,
DepartmentID = departmentID,
URL = "http://www.fineartschool.net/Trigonometry",
Title = "New Onsite Course",
Credits = 4
};
// Add the course to the department.
newDepartment.Courses.Add(newCourse);
// The newly create objects are marked as added, the service will insert these into the store.
service.UpdateDepartment(newDepartment);
// Let’s make few more changes to the saved object.
// Since the previous changes have now been persisted, call AcceptChanges to
// reset the ChangeTracker on the objects and mark the state as ObjectState.Unchanged.
// Note, AcceptChanges sets the tracking on, so you do not need to call StartTracking
// explicitly.
newDepartment.AcceptChanges();
newCourse.AcceptChanges();
// Because the change tracking is enabled
// the following change will set newCourse.ChangeTracker.State to ObjectState.Modified.
newCourse.Credits = 6;
service.UpdateDepartment(newDepartment);
}
}
/// <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.");
}
}
}
private void FixupDepartment(Department previousValue)
{
if (IsDeserializing)
{
return;
}
if (previousValue != null && previousValue.Courses.Contains(this))
{
previousValue.Courses.Remove(this);
}
if (Department != null)
{
if (!Department.Courses.Contains(this))
{
Department.Courses.Add(this);
}
DepartmentID = Department.DepartmentID;
}
if (ChangeTracker.ChangeTrackingEnabled)
{
if (ChangeTracker.OriginalValues.ContainsKey("Department")
&& (ChangeTracker.OriginalValues["Department"] == Department))
{
ChangeTracker.OriginalValues.Remove("Department");
}
else
{
ChangeTracker.RecordOriginalValue("Department", previousValue);
}
if (Department != null && !Department.ChangeTracker.ChangeTrackingEnabled)
{
Department.StartTracking();
}
}
}