Message or a type that has MessageContractAttribute and other parameters of different types

Question

I\'m developing WCF services where some classes have the [MessageContract] attribute, and some don\'t.

When I try to run the services I get this error mess

Answer 1

No, it means that you have multiple parameters on the method and some of them are not messages. Try posting the interface to your service.

This blog post explains:

... problem is that message contracts cannot be used at the same time as other parameter types. In this case, the return value of the operation is a string. Return values are just another output parameter, so this operation is mixing a message contract message with a primitive parameter type. This fails because message contracts give you control of the layout of the SOAP message, preventing the system from melding in these additional parameters.

Important note:

By the way, the error message you get when you try to mix message contracts looks like this.

Answer 2

When you are using Message object as a parameter, the method should return void

Answer 3

If you have the issue with mixed types of primitive(such as string) and MessageContract as the other type, i.e. one class as return and a string parameter, one way I solved this was switching from MessageContract to DataContract.

The other way to solve this would be to create a class to hold your primitive type as a property, so that both your return and parameter can implement MessageContract.

Answer 4

Solved!

I can't return String, I have return Greeting object to the client.

using System;
using System.ServiceModel;
using System.Net.Security;

namespace com.blogspot.jeanjmichel.model
{
    [MessageContract]
    public class Greeting
    {
        private String userGreeting;

        private void SetGreeting()
        {
            DateTime now = DateTime.Now;

            if (now.Hour >= 7 && now.Hour <= 11)
            {
                this.userGreeting = "Good morning";
            }
            else if (now.Hour >= 12 && now.Hour <= 17)
            {
                if (now.Hour == 12 || now.Hour == 13)
                {
                    this.userGreeting = "Good afternoon, it's lunch time!";
                }
                else
                {
                    this.userGreeting = "Good afternoon";
                }
            }
            else if (now.Hour >= 18 && now.Hour <= 20)
            {
                this.userGreeting = "Good evening";
            }
            else
            {
                this.userGreeting = "Good night";
            }
        }

        [MessageBodyMember(Order = 1, ProtectionLevel = ProtectionLevel.EncryptAndSign)]
        public String UserGreeting
        {
            get { return this.userGreeting; }
        }

        public Greeting()
        {
            this.SetGreeting();
        }
    }
}

using System;
using System.ServiceModel;
using com.blogspot.jeanjmichel.model;

namespace com.blogspot.jeanjmichel.services.contract
{
    [ServiceContract(Namespace = "http://jeanjmichel.blogspot.com/services/v0.0.1")]
    public interface IGetGreeting
    {
        [OperationContract]
        Greeting GetGreeting(Credential credential);
    }
}

using System;
using System.ServiceModel;
using com.blogspot.jeanjmichel.services.contract;
using com.blogspot.jeanjmichel.model;

namespace com.blogspot.jeanjmichel.services
{
    [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall,
                     Namespace = "http://jeanjmichel.blogspot.com/services/v0.0.1")]
    public class GetGreetingService: IGetGreeting
    {
        public Greeting GetGreeting(Credential credential)
        {
            if (String.IsNullOrEmpty(credential.Token))
            {
                throw new FaultException("Inform the security phrase, and try again.");
            }
            else
            {
                if (credential.Token.Equals("mySeCuriTyP@ss"))
                {
                    Greeting g = new Greeting();
                    return g;
                }
                else
                {
                    throw new FaultException("Wrong password.");
                }
            }
        }
    }
}

Answer 5

This basically means that a particular operation is using a combination of message contract types and primitive types in any of the following combinations:

MixType1: Contract type and primitive types as operation parameters
MixType2: Contract type as a parameter and primitive type as return type
MixType3: Primitive type as a parameter and Contract type as return type

Any of the scenarios listed above would generate the error.