Access MethodInfo in IOperationInvoker implementation

Question

I have implemented IOperationInvoker to customize the WCF invokation. In Invoke method I want to access custom attributes of the method which is invoked by OperationInvoker. I have written the following code. But, it's not giving the custom attributes which are specified on that method.

public MyOperationInvoker(IOperationInvoker operationInvoker, DispatchOperation dispatchOperation)
{
            this.operationInvoker = operationInvoker;
}

public object Invoke(object instance, object[] inputs, out object[] outputs)
{
   MethodInfo mInfo=(MethodInfo)this.operationInvoker.GetType().GetProperty("Method").
                     GetValue(this.operationInvoker, null);
object[] objCustomAttributes = methodInfo.GetCustomAttributes(typeof(MyAttribute), true);

}

Answer 1

At runtime, the OperationInvoker has type SyncMethodInvoker which contains the MethodInfo. But due to its protection level, we can't cast the OperationInvoker to SyncMethodInvoker. However, there's a MethodInfo object in the OperationDescription. So what I usually do is pass the MethodInfo in the IOperationBehavior.ApplyDispatchBehavior method into the constructor of CustomOperationInvoker.

public class OperationBehaviourInterceptor : IOperationBehavior
{
  public void ApplyDispatchBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.DispatchOperation dispatchOperation)
  {
    MethodInfo currMethodInfo = operationDescription.SyncMethod;

    var oldInvoker = dispatchOperation.Invoker;
    dispatchOperation.Invoker = new OperationInvokerBase(oldInvoker,currMethodInfo);
  }

  // other method
}

public class CustomOperationInvoker : IOperationInvoker
{
  private IOperationInvoker oldInvoker;
  private MethodInfo methodInfo;
  public CustomOperationInvoker(IOperationInvoker oldOperationInvoker, MethodInfo info)
  {
    this.oldInvoker = oldOperationInvoker;
    this.methodInfo = info;
  }

  // then you can access it 
}