FaultException and custom exception WCF

Question

I have a question on how to send a custom exception as FaultException. It works when I use a system Exception like ArgumentException, but if I change it to my custom exception "TestException" it fails. I can’t get the configuration for the service reference, when I try to add it.

Works:

[OperationContract]
[FaultContract(typeof(ArgumentException))]
[TransportChannel TestMethod ();


public Void TestMethod()
{
            throw new FaultException<ArgumentException>(new ArgumentException("test"), new FaultReason("test"));
}

Doesn’t work:

[OperationContract]
[FaultContract(typeof(TestException))]
[TransportChannel TestMethod ();


public Void TestMethod()
{
            throw new FaultException<TestException>(new TestException("test"), new FaultReason("test"));
}

My “TestException” looks like this:

[Serializable()]
public class TestException: Exception
{
    public TestException () : base() { }
    public TestException (string message) : base(message) { }
    public TestException (string message, Exception innerException) : base(message, innerException) { }
    public TestException (System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
}

I guess I have to add a DataContract on the custom object, but I don’t understand why it won’t work like it is, since the ArgumentException works. Can someone enlighten me?

Thanks for help :)

Verve

Odd. I had a similar problem and got it to work without having to add a [DataContract] attribute to my custom exception. I was just missing the constructor that took SerializationInfo and SerializationContext. Adding that constructor worked for me. – Chromatograph

@JeffBridgman You probably meant Serialization.StreamingContext, not SerializationContext – Godinez

@Teejay, correct. I referencing this constructor but typed the wrong thing. – Chromatograph

Answer 1

You do need to mark it with [DataContract] as described at this page: http://msdn.microsoft.com/en-us/library/ms576199.aspx.

I'm assuming (but don't know for sure) that ArgumentException works because it's known on both sides of the wire (assuming you're using .NET on each side). Without declaring your exception as a DataContract, it can't be described and serialized/deserialized correctly by the DataContractSerializer.

Foucault

This post at MSDN seems to imply that you can mark it as both [Serializable] and [DataContract]. I personally got an error when navigating to the .svc page in my browser complaining that Type 'TestException' cannot be ISerializable and have DataContractAttribute attribute. – Chromatograph

Answer 2

You certainly need to Mark it as DataContract. It is a custom type, which the other side (your client) does not know.

Cown