windows xp .net framework 4.0 HttpWebRequest 报The underlying connection was closed,基础连接已关闭

windows xp .net framework 4.0 HttpWebRequest 报The underlying connection was closed,基础连接已关闭,错误的解决方法

在 HttpWebRequest 请求的上方加入以下代码

ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;