.NET 4.0 / 4.5 serialization - System.Runtime.Serialization.InvalidDataContractException: No set method for property x in type y

Last night I observed a difference in the handling of WCF service contracts between .NET 4.0 and 4.5.

The service has an interface that allows inherited types to be passed over it.

[ServiceKnownType("GetKnownProductTypes", typeof(KnownTypeHelper))]

public interface IDealBookingService
{
  [OperationContract]
  int SaveProduct(ProductBase product);
}

 

One of these derived types, CommStorProduct, had a property that did not have a set accessor:

[DataMember]
public DateTime StartDate3
{
get { return StartDate; }
}

Running this on a developer’s machine, no problems were encountered.
However, deploying this to a downstream environment, the following error was thrown when the service started:

Unhandled Exception: System.Runtime.Serialization.InvalidDataContractException:

No set method for property 'StartDate3' in type 'ServiceContract.MyDerivedType'.

   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.Throw

InvalidDataContractException(String message, Type type)

   at System.Runtime.Serialization.ClassDataContract.ClassDataContractCriticalHe

lper.ImportDataMembers()

   at System.Runtime.Serialization.ClassDataContract.ClassDataContractCriticalHe

lper..ctor(Type type)

   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.Creat

eDataContract(Int32 id, RuntimeTypeHandle typeHandle, Type type)

   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.GetDa

taContractSkipValidation(Int32 id, RuntimeTypeHandle typeHandle, Type type)

   at System.Runtime.Serialization.XsdDataContractExporter.GetSchemaTypeName(Typ

e type)

   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.Va

lidateDataContractType(Type type)

   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter..c

tor(OperationDescription description, DataContractFormatAttribute dataContractFo

rmatAttribute, DataContractSerializerOperationBehavior serializerFactory)

   at System.ServiceModel.Description.DataContractSerializerOperationBehavior.Ge

tFormatter(OperationDescription operation, Boolean& formatRequest, Boolean& form

atReply, Boolean isProxy)

   at System.ServiceModel.Description.DataContractSerializerOperationBehavior.Sy

stem.ServiceModel.Description.IOperationBehavior.ApplyDispatchBehavior(Operation

Description description, DispatchOperation dispatch)

   at System.ServiceModel.Description.DispatcherBuilder.BindOperations(ContractD

escription contract, ClientRuntime proxy, DispatchRuntime dispatch)

   at System.ServiceModel.Description.DispatcherBuilder.InitializeServiceHost(Se

rviceDescription description, ServiceHostBase serviceHost)

   at System.ServiceModel.ServiceHostBase.InitializeRuntime()

   at System.ServiceModel.ServiceHostBase.OnBeginOpen()

   at System.ServiceModel.ServiceHostBase.OnOpen(TimeSpan timeout)

   at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)

   at Service.Host.ServiceController.Start() in C:\Source Code\Test\TestWCF\Serv

ice.Host\ServiceController.cs:line 14

   at Service.Host.Program.Main(String[] args) in C:\Source Code\Test\TestWCF\Se

rvice.Host\Program.cs:line 13

 

The developer’s machine had .NET 4.5 installed. After installing .NET 4.5 to the target machine the problem was resolved. (The other code-based solution was to add an internal set property to the data class as the exception hinted).

Inspecting the .NET code, it can be seen there is a runtime serialization difference between the two versions - .NET 4.5 is more forgiving than the earlier version for this scenario.

 

I haven’t found any documentation about serialization changes between the versions.