How can I get reference to ModelState property in my ActionFilter?

This is my class which is basically used for UnitForWork pattern i.e save everything in a transaction:

public class TestFilterAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            base.OnActionExecuted(filterContext);
            if (filterContext.HttpContext == null)
                throw new NullReferenceException("null");
            else
            {
                ObjectContext objectContext =开发者_JS百科 (ObjectContext)filterContext.HttpContext.Items
                                                                [ObjectContextManager.TestContext];

                if (objectContext != null)
                {
                    objectContext.SaveChanges();
                }
            }
        }
    }

This works fine. However, I also want to make sure that it is only saved if the ModelState.IsValid property is true in my action method. How can I do so?

filterContext.Controller gives you reference of ControllerBase rather than Controller. if you cast it to Controller it will give you access to ModelState which is a public property of controller class like

var val = ((Controller)filterContext.Controller).ModelState.IsValid; 

Currently, i have no idea what are the implications of this casting. Please inquire a bit about consequences before using.
UPDATE:
you can also access Modelstate property like

filterContext.Controller.ViewData.ModelState

and it involves no casting