I made some research about this topic and I found this post from Matt Tavis.
Basically we need to define our service contract in the following manner to support WCF and ASMX:
namespace ServiceContracts
{
[ServiceContract]
[WebServiceBinding(ConformsTo=WsiProfiles.BasicProfile1_1,EmitConformanceClaims=true)]
public interface IEmployeeManager
{
[OperationContract]
[WebMethod]
Employee getEmployee(int employeeId);
}
}
The System.Web.Services.WebServicesBindingAttribute class is used to specify a binding that describe things like the service location, its namespace, conformance to the WS-I Basic Profile, etc.
In the .NET Framework 2.0, this attribute and the WebMethod attribute may now be applied to interfaces.
So we can have Interface-Based Service Contracts that target ASMX also.
Pablo