检索列表的文件谷歌驱动器使用.net sdk

我试图从谷歌驱动器获取文件列表，我使用他们提供的例子，因为它是:

public static List<File> RetrieveAllFiles(DriveService service)
    {
        List<File> result = new List<File>();
        FilesResource.ListRequest request = service.Files.List();
        do
        {
            try
            {
                FileList files = request.Fetch();
                result.AddRange(files.Items);
                request.PageToken = files.NextPageToken;
            }
            catch (Exception e)
            {
                Console.WriteLine("An error occurred: " + e.Message);
                request.PageToken = null;
            }
        } while (!String.IsNullOrEmpty(request.PageToken));
        return result;
    }

它总是返回文件count = 0，而我很确定登录帐户有许多文件!还有别的要求吗?

验证:

  public static IAuthenticator GetCredentials(String authorizationCode, String state)
    {
        String emailAddress = "";
        try
        {
            IAuthorizationState credentials = ExchangeCode(authorizationCode);
            Userinfo userInfo = GetUserInfo(credentials);
            String userId = userInfo.Id;
            emailAddress = userInfo.Email;
            if (!String.IsNullOrEmpty(credentials.RefreshToken))
            {
                StoreCredentials(userId, credentials);
                return GetAuthenticatorFromState(credentials);
            }
            else
            {
                credentials = GetStoredCredentials(userId);
                if (credentials != null && !String.IsNullOrEmpty(credentials.RefreshToken))
                {
                    return GetAuthenticatorFromState(credentials);
                }
            }
        }
        catch (CodeExchangeException e)
        {
            Console.WriteLine("An error occurred during code exchange.");
            // Drive apps should try to retrieve the user and credentials for the current
            // session.
            // If none is available, redirect the user to the authorization URL.
            e.AuthorizationUrl = GetAuthorizationUrl(emailAddress, state);
            throw e;
        }
        catch (NoUserIdException)
        {
            Console.WriteLine("No user ID could be retrieved.");
        }
        // No refresh token has been retrieved.
        String authorizationUrl = GetAuthorizationUrl(emailAddress, state);
        throw new NoRefreshTokenException(authorizationUrl);
    }
     internal static Google.Apis.Drive.v2.DriveService BuildService(IAuthenticator credentials)
    {
        return new Google.Apis.Drive.v2.DriveService(credentials);
    }

  public ActionResult Index(string state, string code)
    {
        try
        {
            List<File> files = new List<File>();
            IAuthenticator authenticator = Utils.GetCredentials(code, state);
            // Store the authenticator and the authorized service in session
            Session["authenticator"] = authenticator;
            DriveService service = Utils.BuildService(authenticator);
            if (authenticator != null && service != null)
            {
                files = GoogleDriveHelper.RetrieveAllFiles(service);
                return View(files);
            }
        }
        catch (CodeExchangeException)
        {
            if (Session["service"] == null || Session["authenticator"] == null)
            {
                Response.Redirect(Utils.GetAuthorizationUrl("", state));
            }
        }
        catch (NoRefreshTokenException e)
        {
            Response.Redirect(e.AuthorizationUrl);
        }
     return View();
   }