ASP.Net MVC输出缓存：指令或配置设置配置文件必须指定'varyByParam'属性

I encountered the above error message after applying the OutputCache attribute on ActionResult methods with no input parameters - why would I use VaryByParams in this case? Is this a bug in ASP.Net MVC or is there a way of using OutputCache without setting this property?I encountered the above error message after app