Question

So let’s say that I need to update a list of objects.

      using(db)
      {
          repository = new Repository<Publication>(db);
          foreach (KeyValuePair<int,int> item in publications)
          {
                Publication publication = repository.GetById(item.Key);
                if (publication != null)
                {
                    publication.Quantity = publication.Quantity - item.Value;
                    if (publication.Quantity > 0)
                        db.Publication.Attach(publication);
                }
          }
          try
          {
              db.SaveChanges();
          }
          catch (DbUpdateConcurrencyException e)
          {
              throw new Exception("Could not update the database", e);
          }
        }
    }

When I tried to save all the objects, if someone fails, it should be in the catch block, but my question is: how can I get the specific object that throws the exception?

Answer 1

You’re catching DbUpdateConcurrencyException, which has an Entries property, documented as:

Gets DbEntityEntry objects that represent the entities that could not be saved to the database.

So basically that gives you all the problematic ones.