取得网站的根目录的URL网址的C#实现代码

/// <summary>
/// 取得网站的根目录的URL
/// </summary>
/// <returns></returns>
public static string GetRootURI()
{
    string AppPath = "";
    HttpContext HttpCurrent = HttpContext.Current;
    HttpRequest Req;
    if (HttpCurrent != null)
    {
Req = HttpCurrent.Request;

string UrlAuthority = Req.Url.GetLeftPart(UriPartial.Authority);
if (Req.ApplicationPath == null || Req.ApplicationPath == "/")
    //直接安装在   Web   站点  
    AppPath = UrlAuthority;
else
    //安装在虚拟子目录下  
    AppPath = UrlAuthority + Req.ApplicationPath;
    }
    return AppPath;
}