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I'm trying to create a simple Lightswitch application that contains one table ("Transaction" entity) and one view ("Invoice" entity). In this case, the Invoices view is generated from the Transactions table by grouping on Transactions.InvoiceId. The view then references the table through a one-to-many relationship such that Invoice shows up as a navigation property on Transaction, and Transactions shows up as a navigation property on Invoice. Everything works 100% perfectly until I try to create a new Transaction and save it, at which time a validation rule within Lightswitch fires saying "Invoice: The referenced Invoice is either not set or no longer exists." It's correct that the invoice doesn't exist--the Transaction I'm trying to save will be the first one of the new Invoice.

Currently I'm circumventing this problem by handling the Saving event and manually creating the Transaction in my own DataWorkspace, but that feels like a hack and doesn't allow me to use Lightswitch's built-in validation against the other fields in my Transaction entity.

Is there any way I can either tell Lightswitch to skip validation on the Invoice navigation property but leave the others intact? Or are there any other ways I can accomplish what I'm trying to do?

Mike
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1 Answers1

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The Saving event you mention is the Invoice_Saving method?

Your relationship provides a "Transactions" navigation property for the Invoice. That's how you need to create the new transaction, in the Incoice_Saving method, add:

VB: Me.Transactions.AddNew()

C#: this.Transactions.AddNew();

If you do it that way, it doesn't matter that the invoice hasn't been saved yet, it will all be taken care of during the save process.

Yann Duran
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  • The problem that this is the first Transaction for a new invoice -- therefore there is no Invoice object to which to add the transaction. Only after the Transaction is saved will the Invoice exist in the Invoices view. – Mike Jun 30 '12 at 20:52
  • You're making things hard for yourself by doing it that way around. "handling the Saving event and manually creating the Transaction in my own DataWorkspace" sounded like it was the Invoice_Saving method. So if it's Transaction_Saving method you're actually using, then you can add these two lines: "Dim newInvoice = New Invoice()", "Me.Invoice = newInvoice". At least I think you can. I wouldn't do it this way around, so I'm not 100% sure. – Yann Duran Jul 01 '12 at 23:45
  • I tried that but Sql complains about trying to insert a new record into a view. – Mike Jul 02 '12 at 22:46
  • Oh! It's an actual SQL View? Views in attached data sources are read-only. – Yann Duran Jul 03 '12 at 03:48
  • Yes, that's the source of the problem. Lightswitch is attempting to write to a view and there doesn't seem to be any way to stop it. – Mike Jul 07 '12 at 16:04