asp.net 获取网站根地址

 1 public static string GetSiteRoot()
 2         {
 3             string port = System.Web.HttpContext.Current.Request.ServerVariables["SERVER_PORT"];
 4             if (port == null || port == "80" || port == "443")
 5             {
 6                 port = "";
 7             }
 8             else
 9             {
10                 port = ":" + port;
11             }
12             string protocol = System.Web.HttpContext.Current.Request.ServerVariables["SERVER_PORT_SECURE"];
13             if (protocol == null || protocol == "0")
14             {
15                 protocol = "http://";
16             }
17             else
18             {
19                 protocol = "https://";
20             }
21             string sOut = protocol + System.Web.HttpContext.Current.Request.ServerVariables["SERVER_NAME"] + port + System.Web.HttpContext.Current.Request.ApplicationPath;
22             if (sOut.EndsWith("/"))
23             {
24                 sOut = sOut.Substring(0, sOut.Length - 1);
25             }
26             return sOut;
27         }