Databases Reference
In-Depth Information
namespace Unleashed.EntityFramework
{
public class UnleashedObjectContext : ObjectContext
{
private const EntityState ChangedEntityStates =
EntityState.Added | EntityState.Modified | EntityState.Deleted;
public override int
SaveChanges
(SaveOptions options)
{
IEnumerable<ObjectStateEntry> stateEntries = this.
ObjectStateManager
.GetObjectStateEntries(ChangedEntityStates)
.Where(stateEntry => !stateEntry.IsRelationship);
foreach (ObjectStateEntry stateEntry in stateEntries)
this.BeforeSaveChanges(stateEntry);
return base.SaveChanges(options);
}
private void
BeforeSaveChanges
(ObjectStateEntry stateEntry)
{
if (stateEntry.State != EntityState.Deleted)
this.Validate(stateEntry);
}
private void
Validate
(ObjectStateEntry stateEntry)
{
object entity = stateEntry.Entity;
var context = new ValidationContext(entity, null, null);
Validator.
ValidateObject
(entity, context, true);
}
}
}
First, the overridden
SaveChanges
method gets a list of state entries for all changed
entities from the
ObjectStateManager
that keeps track of all entities in the
ObjectContext
.
For each of the changed state entries, it calls the
BeforeSaveChanges
method responsible
for performing all entity-specific actions that need to occur before the changes are saved
to the database. As we continue expanding Entity Framework capabilities to solve real-
world business problems, this method will grow. At this point, however, it is only respon-
sible for validation of the changed entities. The
Validate
method extracts the actual
entity from an
ObjectStateEntry
and calls the familiar
ValidateObject
method of the
Validator
class. If the entity object is invalid, the
ValidateObject
method throws a
