MessageBodyMembers with same return type and name causing exception - Element has already been exported

Question

I am following a pattern that has objects for the Request and Response of a WCF service. I have multple request objects that have the same return type and name. Any help would be greatly appreciated.

I'm getting the following exception:

An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is: System.InvalidOperationException: An exception was thrown in a call to a WSDL export extension: System.ServiceModel.Description.DataContractSerializerOperationBehavior contract: http://tempuri.org/:IService ----> System.InvalidOperationException: The Service.ServiceContract.IService.RetrieveUsers operation references a message element [http://tempuri.org/:WeekEndingId] that has already been exported from the Service.ServiceContract.IService.RetrieveDepartments operation. You can change the name of one of the operations by changing the method name or using the Name property of OperationContractAttribute. Alternatively, you can control the element name in greater detail using the MessageContract programming model.

Edit: I have used the Name attribute on the properties to give them unique names and this does resolve the issue but we are needing to use the name "WeekEndingId" for all requests. I would like to try and find a fix for this while still using the same name for the property.

Listed below are the classes that are causing the issues:

RetrieveDepartmentsRequest:

[MessageContract(WrapperName = "RetrieveDepartmentsRequest", WrapperNamespace = "http://Service.V1")]
    public class RetrieveDepartmentsRequest
    {
        [MessageBodyMember(Order = 0)]
        public int WeekEndingId { get; set; }

        [MessageBodyMember(Order = 1)]
        public string UserId { get; set; }

        [MessageBodyMember(Order = 2)]
        public string MachineName { get; set; }
    }

RetrieveUsersRequest:

[MessageContract(WrapperName = "RetrieveUsersRequest", WrapperNamespace = "http://Service.V1")]
public class RetrieveUsersRequest
{
    [MessageBodyMember(Order = 0)]
    public int WeekEndingId { get; set; }

    [MessageBodyMember(Order = 1)]
    public string UserId { get; set; }

    [MessageBodyMember(Order = 2)]
    public string MachineName { get; set; }
}

IService:

[OperationContract]
[FaultContract(typeof(ServiceFault))]
RetrieveDepartmentsResponse RetrieveDepartments(RetrieveDepartmentsRequest request);

[OperationContract]
[FaultContract(typeof(ServiceFault))]
RetrieveUsersResponse RetrieveUsers(RetrieveUsersRequest request);

Steven Licht Steven Licht · Accepted Answer · 2013-02-28T07:24:32

I believe it's a type conflict. In that: WeekEndingId is an int in RetrieveDepartmentsRequest and a decimal in RetrieveUsersRequest. Use MessageBodyMember's Name property to resolve the conflict. OR just change the name of the property in RetrieveUsersRequest.

OR BETTER yet: shouldn't WeekEndingId always be an int?

MessageBodyMembers with same return type and name causing exception - Element has already been exported

3 Answers