public String GetRefreshToken(String AuthorizedCode)
        {
            string Url = "https://accounts.google.com/o/oauth2/token";

            if (RedirectUri == null)
            {
                RedirectUri = @"http://localhost";
            }

            string Grant_type = "authorization_code";
            string Data       = "code={0}&client_id={1}&client_secret={2}&redirect_uri={3}&grant_type={4}";
            String Param      = String.Format(Data, AuthorizedCode, ClientID, ClientSecret, RedirectUri, Grant_type);

            String Result = WebUtils.HttpPostResult(Url, Param, WebUtils.ContentType.Form);

            GoogleTokenData TokenData = JsonConvert.DeserializeObject <GoogleTokenData>(Result);

            return(TokenData.Refresh_Token);
        }