How to logout FaceBook in window phone 7 - facebook

Question

I have a problem logging out of Facebook on Windows Phone. I have the code to login, but I can't log out of it. Can someone show me how to log out of Facebook on a Windows Phone?
Here's the login code:
private FacebookClient _asyncFbClient;
private string _appID = "";
private string _appSecret = "";
private void StartFacebookLogin(object sender, RoutedEventArgs e)
{
string[] extendedPermissions = new[] { "user_about_me", "publish_stream", "email" };
FacebookClient fb = new FacebookClient();
var oauth = new FacebookOAuthClient { AppId = _appID, AppSecret = _appSecret };
var logout = new FacebookUser();
var parameters = new Dictionary<string, object>
{
{"response_type", "token"},
{"display", "touch"}
};
if (extendedPermissions != null && extendedPermissions.Length > 0)
{
var scope = new StringBuilder();
scope.Append(string.Join(",", extendedPermissions));
parameters["scope"] = scope.ToString();
}
var loginUrl = oauth.GetLoginUrl(parameters);
webBrowser.Navigated += new EventHandler<System.Windows.Navigation.NavigationEventArgs>(CheckForAuth);
webBrowser.Navigate(loginUrl);
}
private void CheckForAuth(object sender, System.Windows.Navigation.NavigationEventArgs e)
{
FacebookOAuthResult result;
if (FacebookOAuthResult.TryParse(e.Uri, out result))
{
if (result.IsSuccess)
{
IsolatedStorageSettings Settings = IsolatedStorageSettings.ApplicationSettings;
MessageBox.Show(result.AccessToken);
access = result.AccessToken;
if (Settings.Contains("MyFacebookAccessToken1"))
Settings["MyFacebookAccessToken1"] = result.AccessToken;
else
Settings.Add("MyFacebookAccessToken1", result.AccessToken);
Settings.Save();
_asyncFbClient = new FacebookClient(result.AccessToken);
_asyncFbClient.GetCompleted += new EventHandler<FacebookApiEventArgs>(_asyncFbClient_GetCompleted);
_asyncFbClient.GetAsync("/me");
}
}
}
Here's the logout code:
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(linkUrl);
request.Method = "GET";
request.BeginGetResponse(new AsyncCallback(LogoutResponse), request);
private void LogoutResponse(IAsyncResult result)
{
string responseData = "";
try
{
HttpWebRequest request = result.AsyncState as HttpWebRequest;
HttpWebResponse response = request.EndGetResponse(result) as HttpWebResponse;
if (response != null && response.StatusCode == HttpStatusCode.OK)
{
Stream stream = response.GetResponseStream();
StreamReader reader = new StreamReader(stream);
responseData = reader.ReadToEnd();
//responseData = true
}
}
catch (Exception ex)
{
Dispatcher.BeginInvoke(() => { MessageBox.Show(ex.Message); });
}
}
I have tried to use Facebook's logout API and get a successful result, but the next time I open the web browser it's already automatically logged in to Facebook again. How can I get it to log out?

Answer 1

I tried quite a few hacks to get this to work... and then Facebook finally updated their documentation with a good answer:
Logout
You can log a user out of their Facebook session by directing them to
the following URL:
https://www.facebook.com/logout.php?next=YOUR_URL&access_token=ACCESS_TOKEN
YOUR_URL must be a URL in your site domain, as defined in the
Developer App.
From http://developers.facebook.com/docs/authentication/

Answer 2

there is no FB Logout, it has been removed.
your best bet is to forget your credentials.

Answer 3

Facebook PHP SDK uses a function like this:
public function getLogoutUrl($params=array()) {
return $this->getUrl(
'www',
'logout.php',
array_merge(array(
'next' => $this->getCurrentUrl(),
'access_token' => $this->getAccessToken(),
), $params)
);
}
Which creates a URL like:
https://www.facebook.com/logout.php?next={YOUR_ENCODED_URL}&access_token={YOUR_ACCESS_TOKEN}
I believe the encoded URL must be owned by the application to whom the access_token belongs.
If you get that URL right, it'll work (just tried for one of my applications).
I'm not 100% sure if it works on windows-phone, but you can give it a try.