public override string GetAuthorizationUrl()
{
var ub = new UriBuilder(AuthorizationCodeUrl);
ub.Query = string.Format("response_type=code&client_id={0}&redirect_uri={1}&state=QQ&scope=get_user_info,add_t,add_pic_t", ClientId, Uri.EscapeDataString(CallbackUrl));
return ub.ToString();
}