MVC过滤器

//AllowMultiple = true:允许多个标签同时都起作用
[AttributeUsage(AttributeTargets.All,AllowMultiple = true)]
public class MyActionFilterAttribute : ActionFilterAttribute
{
    public string Name { get; set; }

    //Action执行之前先执行此方法
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        base.OnActionExecuting(filterContext);
        //HttpContext.Current.Session[""]
        HttpContext.Current.Response.Write("<br />OnActionExecuting Action执行之前先执行此方法 ：" + Name);
    }

    //Action执行之后
    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        base.OnActionExecuted(filterContext);
        HttpContext.Current.Response.Write("<br />OnActionExecuted Action执行之后：" + Name);
    }

    //ActionResult执行之前先执行此方法
    public override void OnResultExecuting(ResultExecutingContext filterContext)
    {
        base.OnResultExecuting(filterContext);
        HttpContext.Current.Response.Write("<br />OnResultExecuting ActionResult执行之前先执行此方法：" + Name);
    }

    //ActionResult执行之后
    public override void OnResultExecuted(ResultExecutedContext filterContext)
    {
        base.OnResultExecuted(filterContext);
        HttpContext.Current.Response.Write("<br />OnResultExecuted ActionResult执行之后：" + Name);
    }
}

[MyActionFilter(Name = "HomeController")]
public class HomeController : Controller
{
    [MyActionFilter(Name = "Index Action")]
    public ActionResult Index()
    {
        Response.Write("<p>Action执行了</p>");

        return Content("<br />ok:视图被渲染<br />");
    }
}

public class MyExceptionFilterAttribute: HandleErrorAttribute
{
    public override void OnException(ExceptionContext filterContext)
    {
        base.OnException(filterContext);

        //当出现了异常的时候，才执行此方法

        //记录日志
        //多个线程同时访问一个日志文件
        //性能非得低。
        //考虑使用内存队列提高性能，Redis
        //加入观察者模式屏蔽写入不同地方的变化点
        //log4net

        //页面跳转到错误页面或者是首页
        HttpContext.Current.Response.Redirect("/Home/Index");
    }
}