gistfile1.cs

 public class NoMethodActionDescriptor : ActionDescriptor {
        public readonly string httpMethod;

        public NoMethodActionDescriptor(string httpMethod)
        {
            this.httpMethod = httpMethod;
        }

        public override object Execute(ControllerContext controllerContext, IDictionary<string, object> parameters)
        { 
            throw new HttpException(405,"No handler for method " + httpMethod);
        }

        public override ParameterDescriptor[] GetParameters()
        {
            return new ParameterDescriptor[] {};
        }

        public override string ActionName
        {
            get { return httpMethod; }
        }

        public override ControllerDescriptor ControllerDescriptor
        {
            get { return null; }
        }
    }