WCF Notes

Instance Management

WCF supports three types of instance activation: per-call/Sessionful/singleton service.

[ServiceContract]
interface IMyContract
{...}

[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single)]
[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession)]
[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)]
class MyService : IMyContract
{...}

Operations

WCF supports three invocation model: Request-Reply/One-Way/Callback.

[ServiceContract]
interface IMyContract
{
   [OperationContract(IsOneWay = true)]
   void MyMethod( );
}

[ServiceContract(CallbackContract = typeof(ISomeCallbackContract))]
interface IMyContract
{
   [OperationContract]
   void DoSomething( );
}

Fault Contracts

The client can actually encounter three types of errors when trying to invoke the service: communication errors, errors related to the state of the proxy, service-thrown exceptions.

By default, any exception thrown by the service reaches the client as a FaultException.

Transactions

Transaction Flow: Allowed, NotAllowed, Mandatory.

Transaction Protocols

Transaction management protocols: Lightweight, OleTx(RPC), WS-Atomic Transaction (WSAT).

Transaction Managers

The three transaction managers are the Lightweight Transaction Manager (LTM), the Kernel Transaction Manager (KTM), and the Distributed Transaction Coordinator (DTC).