ASP.NET MVC ActionFilter parameter binding

Question

If you have a model-bound parameter in an action method, how can you get to that parameter in an action filter?

[MyActionFilter]
public ActionResult Edit(Car myCar)
{
    ...
}

public class MyActionFilterAttribute : ActionFilterAttribute
{
    public void OnActionExecuted(ActionExecutedContext filterContext)
    {
        //I want to access myCar here
    }

}

Is there anyway to get myCar without going through the Form variables?

Answer 1

Not sure about OnActionExecuted but you can do it in OnActionExecuting:

public class MyActionFilterAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        // I want to access myCar here

        if(filterContext.ActionParameters.ContainsKey("myCar"))
        {
            var myCar = filterContext.ActionParameters["myCar"] as Car;

            if(myCar != null)
            {
                // You can access myCar here
            }
        }
    }
}

Answer 2

public class MyActionFilterAttribute : ActionFilterAttribute
{
    private Car _myCar;

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if(filterContext.ActionParameters.ContainsKey("myCar"))
        {
            _myCar = filterContext.ActionParameters["myCar"] as Car;
        }

        // or the shorter less readable version:
        //_myCar = filterContext.ActionParameters
            //.SingleOrDefault(kvp => kvp.Key == "myCar").Value as Car;
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        // I want to access myCar here


        if(_myCar != null)
        {
            // You can access myCar here
        }

    }
}