Return Object() from WCF VB.NET

Question

I have a WCF service which has this function:

 Public Function ObtenerGruposYAnalisisYConclusionesPredefinidas() As Object() Implements ISrvConclusionesNotas.ObtenerGruposYAnalisisYConclusionesPredefinidas
    Dim conclus As New ConclusionesNotasDL
    Return conclus.ObtenerGruposYAnalisisYConclusionesPredefinidas()
End Function

which returns the values specified here:

Public Function ObtenerGruposYAnalisisYConclusionesPredefinidas() As Object()
    Dim objeto(2) As Object
    objeto(0) = ObtenerGruposAnalisis()
    objeto(1) = ObtenerAnalisis()
    objeto(2) = ObtenerConclusionesPredefinidas()
    Return objeto
End Function

Each one of this functions returns a List of entities.
If I call this functions individually they return their values ok. But what I want is to make only one call to the service and no several!
I want to be able to receive it in another application like this:

Dim concluNotas As SrvConclusionesYNotas.SrvConclusionesNotasClient = New SrvConclusionesYNotas.SrvConclusionesNotasClient
    Dim objeto() As Object = concluNotas.ObtenerGruposYAnalisisYConclusionesPredefinidas()

What should I do?

Do I have to serialize it some way? The process is working great in the service, but in the other app is not receiving the object and I have an exception which suggests this is not supported by http (sending a object array).

carlosfigueira · Accepted Answer · 2011-08-17 20:27:20Z

2

WCF only serializes (and deserializes) object types it "knows" about. If your operation returns Object(), WCF at that point only knows about Object() itself and Object. You'll need to indicate to WCF which actual objects can be serialized (and deserialized), by using the ServiceKnownType attribute, like in the example below.

Public Class StackOverflow_7098691
    Public Class GruposAnalisis
        Public Text As String
    End Class
    Public Class Analisis
        Public Text As String
    End Class
    Public Class ConclusionesPredefinidas
        Public Text As String
    End Class

    <ServiceContract()>
    Public Interface ITest
        <OperationContract()>
        <ServiceKnownType(GetType(GruposAnalisis))>
        <ServiceKnownType(GetType(Analisis))>
        <ServiceKnownType(GetType(ConclusionesPredefinidas))>
        Function ObtenerGruposYAnalisisYConclusionesPredefinidas() As Object()
    End Interface

    Public Class Service
        Implements ITest

        Public Function ObtenerGruposYAnalisisYConclusionesPredefinidas() As Object() Implements ITest.ObtenerGruposYAnalisisYConclusionesPredefinidas
            Dim objeto(2) As Object
            objeto(0) = ObtenerGruposAnalisis()
            objeto(1) = ObtenerAnalisis()
            objeto(2) = ObtenerConclusionesPredefinidas()
            Return objeto
        End Function

        Function ObtenerGruposAnalisis() As GruposAnalisis
            Dim result As GruposAnalisis = New GruposAnalisis()
            result.Text = "GruposAnalisis"
            Return result
        End Function

        Function ObtenerAnalisis() As Analisis
            Dim result As Analisis = New Analisis()
            result.Text = "Analisis"
            Return result
        End Function

        Function ObtenerConclusionesPredefinidas() As ConclusionesPredefinidas
            Dim result As ConclusionesPredefinidas = New ConclusionesPredefinidas()
            result.Text = "ConclusionesPredefinidas"
            Return result
        End Function
    End Class

    Public Shared Sub Test()
        Dim baseAddress As String = "http://" + Environment.MachineName + ":8000/Service"
        Dim host As ServiceHost = New ServiceHost(GetType(Service), New Uri(baseAddress))
        host.AddServiceEndpoint(GetType(ITest), New BasicHttpBinding(), "")
        host.Open()
        Console.WriteLine("Host opened")

        Dim factory As ChannelFactory(Of ITest) = New ChannelFactory(Of ITest)(New BasicHttpBinding(), New EndpointAddress(baseAddress))
        Dim proxy As ITest = factory.CreateChannel()

        Dim result = proxy.ObtenerGruposYAnalisisYConclusionesPredefinidas()
        For Each grupo In result
            Console.WriteLine(grupo)
        Next
    End Sub
End Class

answered Aug 17, 2011 at 20:27

carlosfigueira

87.7k14 gold badges137 silver badges176 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

euther Over a year ago

i'm using linq to sql and i added the three <ServiceKnownType(GetType(LINQTOSQLENTITY))> but still not working

carlosfigueira Over a year ago

What are the exact types which your service is returning? Also, can you enable tracing at the server? The traces will tell you exactly what type is causing a problem.

euther Over a year ago

yes i can enable tracing, i'll be honest i've never done that before, i'll investigate it and when i do it, i'll write again. thanks

carlosfigueira Over a year ago

You can find information on enabling tracing at msdn.microsoft.com/en-us/library/ms733025.aspx

Collectives™ on Stack Overflow

Return Object() from WCF VB.NET

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related