Entity Framework with ASP.NET MVC. Updating entity problem
- by Kitaly
Hi people. I'm trying to update an entity and its related entities as well. For instance, I have a class Car with a property Category and I want to change its Category. So, I have the following methods in the Controller:
public ActionResult Edit(int id)
{
var categories = context.Categories.ToList();
ViewData["categories"] = new SelectList(categories, "Id", "Name");
var car = context.Cars.Where(c => c.Id == id).First();
return PartialView("Form", car);
}
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Edit(Car car)
{
var category = context.Categories.Where(c => c.Id == car.Category.Id).First();
car.Category = category;
context.UpdateCar(car);
context.SaveChanges();
return RedirectToAction("Index");
}
The UpdateCar method, in ObjectContext class, follows:
public void UpdateCar(Car car)
{
var attachedCar = Cars.Where(c => c.Id == car.Id).First();
ApplyItemUpdates(attachedCar, car);
}
private void ApplyItemUpdates(EntityObject originalItem, EntityObject updatedItem)
{
try
{
ApplyPropertyChanges(originalItem.EntityKey.EntitySetName, updatedItem);
ApplyReferencePropertyChanges(updatedItem, originalItem);
}
catch (InvalidOperationException ex)
{
Console.WriteLine(ex.ToString());
}
}
public void ApplyReferencePropertyChanges(IEntityWithRelationships newEntity, IEntityWithRelationships oldEntity)
{
foreach (var relatedEnd in oldEntity.RelationshipManager.GetAllRelatedEnds())
{
var oldRef = relatedEnd as EntityReference;
if (oldRef != null)
{
var newRef = newEntity.RelationshipManager.GetRelatedEnd(oldRef.RelationshipName, oldRef.TargetRoleName) as EntityReference;
oldRef.EntityKey = newRef.EntityKey;
}
}
}
The problem is that when I set the Category property after the POST in my controller, the entity state changes to Added instead of remaining as Detached.
How can I update one-to-one relationship with Entity Framework and ASP.NET MVC without setting all the properties, one by one like this post?
