Question

I have a WCF Contract outlining a test method that just returns an instance of a class across WCF using protobuf-net. I can serialize and deserialize in a test application but when I make the request via WCF the response the class instance exists, but all its properties are null.

Here are the relevant config files and class definitions:

[ProtoContract]
public class TestClass
{
    [ProtoMember(1)]
    public int TestInt { get; set; }

    [ProtoMember(2)]
    public string TestString { get; set; }
}

...

[ServiceContract]
public interface ITestService
{
    [OperationContract]
    [ProtoBehavior]
    TestClass RunTest(int x);
}

...

<extensions>
    <behaviorExtensions>
        <add name="protobuf" type="ProtoBuf.ServiceModel.ProtoBehaviorExtension, protobuf-net, Version=1.0.0.282, Culture=neutral, PublicKeyToken=257b51d87d2e4d67" />
    </behaviorExtensions>
</extensions>

<endpointBehaviors>
    <behavior name="Proto.Default.EndpointBehavior">
        <protobuf />
    </behavior>
</endpointBehaviors>
<serviceBehaviors>
    <behavior name="Proto.Default.ServiceBehavior">
      <serviceDebug includeExceptionDetailInFaults="true" />
      <serviceMetadata />
      <serviceAuthorization principalPermissionMode="None" />
      <serviceThrottling    maxConcurrentCalls="250"
                            maxConcurrentSessions="200"
                            maxConcurrentInstances="10" />
    </behavior>
</serviceBehaviors>

...

<services>
    <service name="WcfTestService" behaviorConfiguration="Proto.Default.ServiceBehavior">
    <endpoint address=""    binding="netTcpBinding" bindingConfiguration="NetTcpBinding_ITestService"   contract="ITestService" behaviorConfiguration="Proto.Default.EndpointBehavior" />
    <endpoint address="mex" binding="customBinding" bindingConfiguration="myMexTcpBinding" contract="IMetadataExchange" />
    <host>
        <baseAddresses>
            <add baseAddress="net.tcp://localhost:2517/TestService" />
        </baseAddresses>
    </host>
</service>

...

<client>
   <endpoint address="net.tcp://localhost:2517/TestService"
    binding="netTcpBinding" bindingConfiguration="NetTcpBinding_ITestService"
    contract="ITestService" name="TestService"
    behaviorConfiguration="Proto.Default.EndpointBehavior">
    <identity>
        <dns value="localhost" />
    </identity>
</endpoint>
</client>

I can debug the service and see the request come across. The TestClass object is created and returned. I stepped through protobuf-net source code and the deserialize method runs and it just creates a blank instance of TestClass and iterates through the data that is returned but never sets any of the properties.

Oh, I used Mex to generate a proxy.

EDIT

Here is the MEX generated class for TestClass

[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Runtime.Serialization", "4.0.0.0")]
[System.Runtime.Serialization.DataContractAttribute(Name="TestClass", Namespace="http://schemas.datacontract.org/2004/07/TestProject")]
[System.SerializableAttribute()]
public partial class TestClass : object, System.Runtime.Serialization.IExtensibleDataObject, System.ComponentModel.INotifyPropertyChanged {

    [System.NonSerializedAttribute()]
    private System.Runtime.Serialization.ExtensionDataObject extensionDataField;

    [System.Runtime.Serialization.OptionalFieldAttribute()]
    private int TestIntField;

    [System.Runtime.Serialization.OptionalFieldAttribute()]
    private string TestStringField;

    [global::System.ComponentModel.BrowsableAttribute(false)]
    public System.Runtime.Serialization.ExtensionDataObject ExtensionData {
        get {
            return this.extensionDataField;
        }
        set {
            this.extensionDataField = value;
        }
    }

    [System.Runtime.Serialization.DataMemberAttribute()]
    public int TestInt {
        get {
            return this.TestIntField;
        }
        set {
            if ((this.TestIntField.Equals(value) != true)) {
                this.TestIntField = value;
                this.RaisePropertyChanged("TestInt");
            }
        }
    }

    [System.Runtime.Serialization.DataMemberAttribute()]
    public string TestString {
        get {
            return this.TestStringField;
        }
        set {
            if ((object.ReferenceEquals(this.TestStringField, value) != true)) {
                this.TestStringField = value;
                this.RaisePropertyChanged("TestString");
            }
        }
    }

    public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;

    protected void RaisePropertyChanged(string propertyName) {
        System.ComponentModel.PropertyChangedEventHandler propertyChanged = this.PropertyChanged;
        if ((propertyChanged != null)) {
            propertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propertyName));
        }
    }
}

Answer 1

Right; Mex/generation hasn’t included the numbers, but you can add them. In a separate code file (same namespace), add

[ProtoContract]
[ProtoPartialMember(1, "TestInt")]
[ProtoPartialMember(2, "TestString")]
partial class TestClass {}

Sometimes WCF helps, sometimes it is a pain (note it works easy if you have a shared DTO assembly at both ends).

Sometimes WCF gives the right-ish numbers on each DataMember, but off-by-1 – if that happens there’s a tweak you can use to just tell protobuf to use those numbers with an offset.