R – WCF RIA Services – Returning Entity from Invoke Operation

netsilverlight-3.0wcf-ria-services

I was happily using RIA Services JULY 09 version and using a ServiceOperation for a method which takes some parameters and returns Entity.

[ServiceOperation]
public Entity TestMethod(string param1, string param2, bool param3)
{
// do something here
}

But as soon as i UPGRADED to WCF RIA services, I had to change [ServiceOperation] to [Invoke], but now I am getting a compilation error that Entity can not be returned for an Invoke Operation.
I searched here and there and found out that for VS2008 it does not work but for VS 2010 it still works.
I need to know if there's a workaround to do this for VS2008. I don't want this method to have deferred execution like query methods.

Best Answer

No, there isn't a workaround for 2008.

Eventually the VS2010/.NET 4 version of RIA Services will be RTM'd... so I'd suggest using that if you can deploy on top of .net 4.

If you have to stay on 3.5, then a query method is your only route. As a workaround, you can new up a DomainContext, issue a Load call, use the Entities result of the LoadOperation, and then simply discard the DomainContext... in other words you don't need to use the EntitySet/accumulation model if you don't want to for your particular scenario.

Related Solutions

R – WCF RIA Services Business Rule /Database Exception Handling

In the RTM update you'll be able to set the Error property on DomainServiceErrorInfo you want to send back to the client. At that point, you can set it to an instance of a DomainException.

You might be able to get similar behavior by throwing a new DomainException from your OnError, though that would be a hacky workaround (assuming it works).

C# – Ria Services Passing Complex Object as parameter to a query domain service method

Dirty workaround three, is to use the [Invoke] attribute and add a method to the domain service to expose the "complex type", which informs the WCF RIA tooling to create the entity on the client-side:

public ComplexObjectParameter ExposeComplexObjectParameter()
{
    throw new NotSupportedException();
}

I put NotSupportedException in my domain service methods to prevent silent failures if the method is ever called remotely.

I'm not sure about how this solution affects the issue of losing "all RIA tracking functionality". It does not answer how to create a composable query using a complex type as a parameter.

It's dirty, but abstracts the problem closest to the source of problem. The calling and receiving code is cleaner. This maintains the "elegance" at the higher level while pushing the dirty down.

Best Answer

Related Solutions

R – WCF RIA Services Business Rule /Database Exception Handling

C# – Ria Services Passing Complex Object as parameter to a query domain service method

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