Adding WCF service reference with additional DLL breaks

Question

I have the following classes defined in an external assembly from a third-party vendor:

namespace ThirdParty.Vendor.Code
{
  [Serializable]
  [XmlInclude(typeof(Test1Data))]
  [XmlRoot(Namespace = "", IsNullable = false)]
  public abstract class DeviceTestData
  {
    protected DeviceTestData();
  }

  [Serializable]
  [XmlRoot(Namespace = "", IsNullable = false)]
  public class TestData : DeviceTestData
  {
    public TestData();

    public double DoubleValue { get; set; }
    [XmlIgnore]
    public bool DoubleValue ValueSpecified { get; set; }
  }
}

I've added this assembly as a reference to my WCF service called "TestService" so I can write service code that makes use of these types. That all works perfectly.

Now I have a second project to which I need to add a reference to TestService. Adding the reference works fine, but when I write code to use the referenced types and attempt to compile I get the following error:

The type or namespace name 'TestData' could not be found (are you missing a using directive or an assembly reference?)

So I added the vendor's DLL as a reference in the second project and a directive to use the namespace ThirdParty.Vendor.Code, but now I get:

Cannot implicitly convert type 'ThirdParty.Vendor.Code.TestData' to 'ServiceReference.DeviceTestData'

It seems that without the reference to the third-party DLL, the required classes don't get generated, but if I add the reference, they get referenced twice somehow. WTF?

Anyone got any suggestions for how to fix/work around this?

Answer 1

When you generate the service reference, make sure you have the assembly holding the data contract already referenced, and select "Reuse types in referenced assemblies".