CODEWITHSUNDEEP
windows-phone-7
sashaeve
sashaeve

Reputation: 9607

adding and saving new items to the collection

Assume we have an Customer object with collection of Payments.

Initialization:

var dataContext = new TestDataContext();
dataContext.Customers.InsertOnSubmit(new Customer { Id = 1, Name = "Customer1" });
dataContext.SubmitChanges();
var customer = dataContext.Customers.Where(c => c.Id == 1).First();

First case:

customer.Payments.Add(new Payment { Amount = 100, CustomerId = customer.Id });
dataContext.SubmitChanges();
var count = dataContext.Payments.Count(); // count == 0

Second case:

dataContext.Payments.InsertOnSubmit(new Payment { Amount = 100, Customer = customer });
dataContext.SubmitChanges();
var count = dataContext.Payments.Count(); // count == 1

Third case (combined):

customer.Payments.Add(new Payment { Amount = 100, CustomerId = customer.Id });
dataContext.Payments.InsertOnSubmit(new Payment { Amount = 100, Customer = customer });
dataContext.SubmitChanges();
var count = dataContext.Payments.Count(); // count == 2 (!)

I assume that InsertOnSubmit somehow notifies the DataContext object about changes. But just wondered why it's not notified in the first case?

P.S. I am using SQL CE for Windows Phone.

Upvotes: 0

Views: 179

Answers (1)

MaxK
MaxK

Reputation: 625

Have you tried setting the customer reference to Payment.Customer property in the first case?

E.g. customer.Payments.Add(new Payment { Amount = 100, Customer = customer });

I normally wouldn't set IDs explicitly, but make use of the ORM and establish proper relationships between entities.

Upvotes: 3

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