MVC 中创建简单过滤器

1.新建一个类，继承自 ActionFilterAttribute类，并重写OnActionExecuting()方法

 public class LoginFilter:ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            string flag = (string)filterContext.HttpContext.Session["USER_Name"];
            if (flag == null || "".Equals(flag))
            {
                filterContext.Result = new RedirectResult("~/Login/loginUI");
            }
        }
    }

2.使用方法，在对应的控制器类或者是方法添加约束

    [LoginFilter]
    [SecondMenuORMethod(secondMenuORmethod = "SupplierInfo")]
    public class SupplierInfoController : Controller
    {