How can I force WCF to autogenerate WSDLs with required method parameters (minoccurs="1")?

Question

While using WCF and OperationContracts I have the following method defined:

    [OperationContract]
    [FaultContract(typeof(ValidationFault))]
    [FaultContract(typeof(FaultException<ExceptionDetail>))]
    int DoSomething(int someId, MyComplexType messageData);

When this gets translated to a WSDL by the WCF runtime, it ends up with with minoccurs="0" listed for the parameters someId and messageData (and subsequently throws a runtime error if these parameters are missing).

If I generate a proxy using SoapUI I get something that looks like this:

  <com:DoSomething>
     <!--Optional-->
     <com:EventId>1</com:EventId>
     <!--Optional-->
     <com:myComplexType >
        <com:id>1</com:id>
     </com:myComplexType >
  </com:DoSomething>

The id field in MyComplexType is marked up with DataMemeber attribute using IsRequired="true" and thus is exposed as mandatory.

It's obviously quite misleading for the WSDL to specify that a parameter is optional when it isn't, but I can't see any obvious way to markup the OperationContract to force WCF to recognise and expose these parameters as required.

I'm slightly baffled there doesn't seem an obvious way to do this (reading intellisense / msdn / google). Or I'm going blind and overlooking something obvious.

Any clues?

Solution

I've just written a Blog post about this subject, as I ran into the problem myself last week. It explains how you can modify the metadata that WCF generates at runtime.

Aside from downloading the source file, you only need to add an attribute to your contract definition. Like so:

[ServiceContract]
[RequiredParametersBehavior]
public interface ICalculatorService
{
    [OperationContract]
    int Add(int firstValue, int secondValue);
}

Here's the Blog post that explains it in more detail: Controlling WSDL minOccurs with WCF

Comments

[Zack Jannsen]

Interesting approach. Can you tell me if this works with all types (marshal by reference and marshal by value)? I know that nullable types tend to read up as challenges in generated xsd ... I am wondering if this applies to what you are doing as well. Say I was passing several required 'string' parameters.