Namespace constraint attribute

NamespaceConstraint.cs

public class NamespaceConstraint : ActionMethodSelectorAttribute
    {
        public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)
        {
            var dataTokenNamespace = (string)controllerContext.RouteData.DataTokens.FirstOrDefault(dt => dt.Key == "Namespace").Value;
            var actionNamespace = methodInfo?.DeclaringType?.FullName;
            return dataTokenNamespace == actionNamespace;
        }
    }