Alternative to Using an Entity as a Parameter to an Invoke Method in WCF RIA Services

Question

Howdy, ya'll! First question on StackOverflow! :-)

So here's the scenario: We're working on a web app with Silverlight 4 and using WCF RIA Services 1.0 SP1 Beta for the web service. I have my entities in the Entity Framework Designer, but I'm using a slightly-modified ADO.NET C# POCO Entity Generator template to generate the classes.

What I'd like to do is have a method inside a Domain Service with the following signature:

[EnableClientAccess]
public class ResultService : DomainService
{
    [Invoke]
    public SerializableResult CalculateResult(EntityOne e1, EntityTwo e2);
}

I am returning both EntityOne and EntityTwo to the client through queries in other services, like so:

[EnableClientAccess]
public class EntityOneService : DomainService
{
    public IQueryable<EntityOne> GetEntityOnes();
}

[EnableClientAccess]
public class EntityOneService : DomainService
{
    public IQueryable<EntityTwo> GetEntityTwos();
}

Those classes are successfully being generated in the Silverlight project. The SerializableResult does not have a key.

When I try to compile, I get the following error: "Operation named 'CalculateResult' does not conform to the required signature. Parameter types must be an entity or complex type, a collection of complex types, or one of the predefined serializable types."

In my research, the most helpful information I found were in the comments of this post by Jeff Handley.

Of note, Peter asked in a comment:

I get an 'does not conform to the required signature ...' compile error if my complex object has an [Key] Attribute. When I remove this attribute I can use the object as parameter for an Invoke operation.

Jeff's response:

This is by design. Complex objects cannot have Key properties. If you have a Key the class gets treated as an Entity.

So it sounds as if any further efforts to try to get my method to work will be futile. However, I was wondering if anyone else has come across this problem, and what they did to solve it.

Thanks very much!

Answer 1

I have the following and it works for me.

namespace BusinessApplication2.Web
{
    using System.ComponentModel.DataAnnotations;
    using System.Linq;
    using System.ServiceModel.DomainServices.Hosting;
    using System.ServiceModel.DomainServices.Server;

    [EnableClientAccess()]
    public class DomainService1 : DomainService
    {
        public IQueryable<EntityOne> GetEntityOnes()
        {
            return null;
        }

        public IQueryable<EntityTwo> GetEntityTwos()
        {
            return null;
        }

        [Invoke]
        public SerializableResult GetSerializableResult(EntityOne one, EntityTwo two)
        {
            return new SerializableResult() { Result = "It woooooorrrked!" };
        }
    }

    public class EntityOne
    {
        [Key]
        public int Id { get; set; }
    }

    public class EntityTwo
    {
        [Key]
        public int Id { get; set; }
    }

    public class SerializableResult
    {
        public string Result { get; set; }
    }
}