WCF Known Type from System.Object in Config

Question

I\'m trying to specify a known type in my config, but I\'m having problems with the fact that it derives from Object. I can make it work specifying the known type via attrib

Answer 1

The answer turns out to be it's not possible to do what I want to do in the config file alone. The config above corresponds to the [KnownType] attribute used on DataContracts. There appears to be no way to implement [ServiceKnownType] in the config.

An alternate approach is to use [ServiceKnownType(methodName, type)] attribute with a custom configuration section. The new config looks like this:

The contracts:

[ServiceContract]
[ServiceKnownType("GetServiceKnownTypes", typeof(KnownTypeHelper))]
public interface IContract
{
    [OperationContract]
    void Send(object data);
}

[DataContract]
public class MyData
{
    [DataMember]
    public string Message { get; set; }
}

The helper class that contains the callback that returns the list of known types

public static class KnownTypeHelper
{
    public static IEnumerable GetServiceKnownTypes(ICustomAttributeProvider provider)
    {
        List result = new List();

        ServiceKnownTypesSection serviceKnownTypes = (ServiceKnownTypesSection)ConfigurationManager.GetSection("serviceKnownTypes");
        DeclaredServiceElement service = serviceKnownTypes.Services[((Type)(provider)).AssemblyQualifiedName];

        foreach (ServiceKnownTypeElement knownType in service.KnownTypes)
        {
            result.Add(knownType.Type);
        }

        return result;
    }
}

Information on creating custom config sections can be found here:

http://msdn.microsoft.com/en-us/library/2tw134k3.aspx

http://msdn.microsoft.com/en-us/library/system.configuration.configurationcollectionattribute.aspx