/// <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;
}
/// <summary>
/// 取得网站的根目录的URL
/// </summary>
/// <param name="Req"></param>
/// <returns></returns>
public static string GetRootURI(HttpRequest Req)
{
  string AppPath = "";
  if(Req != null)
  {
    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;
}
/// <summary>
/// 取得网站根目录的物理路径
/// </summary>
/// <returns></returns>
public static string GetRootPath()
{
  string AppPath = "";
  HttpContext HttpCurrent = HttpContext.Current;
  if (HttpCurrent != null)
  {
    AppPath = HttpCurrent.Server.MapPath("~");
  }
  else
  {
    AppPath = AppDomain.CurrentDomain.BaseDirectory;
    if (Regex.Match(AppPath, @"\$", RegexOptions.Compiled).Success)
      AppPath = AppPath.Substring(0, AppPath.Length - 1);
  }
  return AppPath;
}