c# – Google Oauth错误：应至少设置一个客户机密码(已安装或Web

以下是相关代码：

private async Task Run(string filePath)
        {
            UserCredential credential;
            var keyUrl = System.Web.HttpContext.Current.Server.MapPath("~/content/oauth_key.json");
            using (var stream = new FileStream(keyUrl,FileMode.Open,FileAccess.Read))
            {
                credential = await GoogleWebAuthorizationBroker.AuthorizeAsync(
                    GoogleClientSecrets.Load(stream).Secrets,// This OAuth 2.0 access scope allows an application to upload files to the
                    // authenticated user's YouTube channel,but doesn't allow other types of access.
                    new[] { YouTubeService.Scope.YoutubeUpload },"user",CancellationToken.None
                );
            }

            var youtubeService = new YouTubeService(new BaseClientService.Initializer()
            {
                HttpClientInitializer = credential,ApplicationName = Assembly.GetExecutingAssembly().GetName().Name
            });

当我运行它,我得到这个错误：至少应该设置一个客户端秘密(已安装或Web).

但是,在我的json里,没有“客户秘密”：

{
  "private_key_id": "9d98c06b3e730070806dcf8227578efd0ba9989b","private_key": "-----BEGIN PRIVATE KEY-----nMIICdQIBADANBgkqhk etc,"client_email": "546239405652-8igo05a5m8cutggehk3rk3hspjfm3t04@developer.gserviceaccount.com","client_id": "546239405652-8igo05a5m8cutggehk3rk3hspjfm3t04.apps.googleusercontent.com","type": "service_account"
}

所以我假设我忽略了一些东西.
也许我不能使用“服务帐户”？不知道…