if (Request.IsAuthenticated) {.....}

根据一些评论进行编辑通过表格"进行身份验证，请点击此处

edit based on some comments Authenticated via "Forms", check here

HttpContext.Current.User.Identity.IsAuthenticated //将为表单"//协商"正在使用集成的Windows//等

HttpContext.Current.User.Identity.IsAuthenticated // will be "Forms" if using forms based auth // "Negotiate" is using windows integrated // etc

如果使用.net 4.5，并且您想要"SET"用户声明.建议阅读 ClaimsPrincipal

If using .net 4.5 and you wanted "SET" user claims. The ClaimsPrincipal is recommended reading