How do I get the old values of an entity? - entity-framework

Question

How do I get the old values of an entity?
follows the example..
public void Update(User user)
ValidateEntity(user, OperationType.Update);
oldUser = (how do I get the old values ​​(database) of the entity User?)
Set.Attach(user);
Context.ObjectStateManager.ChangeObjectState(user, EntityState.Modified);
Context.SaveChanges();
OnUpdated(user, oldUser);
}

Answer 1

Try this:
public void Update(User user)
ValidateEntity(user, OperationType.Update);
var oldUser = Set.Single(u => u.Id == user.Id);
Context.Detach(oldUser);
Set.Attach(user);
Context.ObjectStateManager.ChangeObjectState(user, EntityState.Modified);
Context.SaveChanges();
OnUpdated(user, oldUser);
}
Or this:
public void Update(User user)
{
ValidateEntity(user, OperationType.Update);
var oldUser = Set.Single(u => u.Id == user.Id);
Set.ApplyCurrentValues(user);
Context.SaveChanges(SaveOptions.DetectChangesBeforeSave);
OnUpdated(user, Context.ObjectStateManager.GetOjectStateEntry(user).OriginalValues);
Context.AcceptAllChanges();
}

Answer 2

I found one way of convert DbDataRecord to entity type using reflection...
where http://www.instanceofanobject.com/2011/01/ef4-dbdatarecord-convertto.html
public static class AnonymousTypeConversion
{
///
/// Converts a single DbDataRwcord object into something else.
/// The destination type must have a default constructor.
///
///
///
///
public static T ConvertTo(this DbDataRecord record)
{
T item = Activator.CreateInstance();
for (int f = 0; f
/// Converts a list of DbDataRecord to a list of something else.
///
///
///
///
public static List ConvertTo(this List list)
{
List result = (List)Activator.CreateInstance>();
list.ForEach(rec =>
{
result.Add(rec.ConvertTo());
});
return result;
}
}