facebook c# sdk - 用户尚未授权应用程序执行此操作

我正在构建一个控制台应用程序，它将将流发布到页面墙上。

问题：我收到“用户尚未授权应用程序执行此操作”。我正在使用 opengraph 来获取访问令牌。

我错过了什么吗？任何帮助是极大的赞赏。谢谢！

// constants
string apiKey = "XXX";
string secret = "XXX";
string pageId = "XXX";

// get access token
string url = string.Format("https://graph.facebook.com/oauth/access_token?client_id={0}&client_secret={1}&grant_type=client_credentials", apiKey, secret); // todo: figure out open graph url
WebRequest req = WebRequest.Create(url);
WebResponse resp = req.GetResponse();
StreamReader reader = new StreamReader(resp.GetResponseStream());
string respStr = reader.ReadToEnd();
string accessToken = respStr.Replace("access_token=", "");

// construct the post
dynamic messagePost = new ExpandoObject();
messagePost.access_token = accessToken;
messagePost.picture = "www.google.com/pic.png";
messagePost.link = "www.google.com";
messagePost.name = "some name";
messagePost.captiion = "some caption";
messagePost.description = "some description";
messagePost.req_perms = "publish_stream";
messagePost.scope = "publish_stream";

// using client
FacebookClient client = new FacebookClient(accessToken);

try // to post the post to the page's wall
{
    var result = client.Post(string.Format("/{0}/feed", pageId), messagePost); 
}
    catch (FacebookOAuthException ex)
{
    // getting caught here, with error msg = "The user hasn't authorized the application to perform this action"
}
catch (FacebookApiException ex)
{
    // ignore
}

访问以下链接后，我能够运行代码并将其成功发布到页面墙上，之后它会显示在喜欢者的新闻提要中。

http://www.facebook.com/login.php?api_key= http://www.facebook.com/login.php?api_key={API_KEY_GOES_HERE}&next=

http://www.facebook.com/connect/prompt_permissions.php?api_key= http://www.facebook.com/connect/prompt_permissions.php?api_key={API_KEY_GOES_HERE}&next={PAGE_ID_GOES_HERE}

感谢 上的回答授权 Facebook 粉丝页面进行状态更新 https://stackoverflow.com/questions/2097665/authorizing-a-facebook-fan-page-for-status-updates