//public string access_token { get; set; }
//public string refresh_token { get; set; } = string.Empty;
//public string user { get; set; }
//public long expires_in { get; set; }
//public string source { get; set; } = "sina";
public bool CheckUseable()
{
return(!string.IsNullOrEmpty(AccessToken) &&
!string.IsNullOrEmpty(User) &&
Untils.FromTimestamp(ExpiresAt) > DateTime.Now);
}