用于确定用户代理的这两个属性之间的差异(如果有)和优点/缺点是什么？ Dim strUserAgt as StringuserAgent = Request.userAgent 与 Dim strUserAgt as String = Request.ServerVariables("HTTP_USER_AGENT") 资料来源：
Dim strUserAgt as String userAgent = Request.userAgent
与
Dim strUserAgt as String = Request.ServerVariables("HTTP_USER_AGENT")
资料来源：
How to determine browser type in server-side code without the BrowserType object in ASP.NET
In ASP.NET, you can access the Request.ServerVariables collection or
use the new Request.UserAgent property to retrieve the HTTP_USER_AGENT
header value.
没有区别,两者都会检索相同的HTTP_USER_AGENT标头值.
检查Request.ServerVariables Collection和IIS Server Variables是否要深入挖掘.这些服务器变量集合值在某种程度上也取决于IIS版本.