Asp.net mvc - Accessing view Model from a custom Action filter

The model is at:

filterContext.Controller.ViewData.Model

I don't know why but filterContext.Controller.ViewData.Model is always null even when the model bind is executed before OnActionExecuted. I found a solution using the OnModelUpdated event to set that property before.

I have the model binder:

public class CustomModelBinder: DefaultModelBinder
{
    protected override void OnModelUpdated(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        controllerContext.Controller.ViewData.Model = bindingContext.Model;
        base.OnModelUpdated(controllerContext, bindingContext);
    }
}

After that you need to set the default binder to your new model binder in Application_Start() section in Global.asax:

ModelBinders.Binders.DefaultBinder = new CustomModelBinder();

Finally you can access your Model in an ActionFilterAttribute:

public class TraceLog : ActionFilterAttribute
{
    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        //filterContext.Controller.ViewData.Model now isn't null
        base.OnActionExecuted(filterContext);
    }
}