Error using facebook C# sdk with WPF web browser - facebook

Question

I am new to facebook c# sdk. I followed the tutorial in this link.
I created an application that displays the user name after log in. Here is my code:
public partial class MainWindow : Window
{
private string appId = "appid";
private string extenededPermissions = "offline_access,publish_stream";
private Uri loginUrl = null;
private string accessToken = null;
private string userName = null;
public MainWindow()
{
InitializeComponent();
}
/// <summary>
/// Function to get the login url
/// with the requested permissions
/// </summary>
private void GetLoginUrl()
{
dynamic parameters = new ExpandoObject();
// add the client id
parameters.client_id = appId;
// add the redirect uri
parameters.redirect_uri = "https://www.facebook.com/connect/login_success.html";
// requested response
parameters.response_type = "token";
// type of display
parameters.display = "popup";
// If extended permissions are present
if (!string.IsNullOrWhiteSpace(extenededPermissions))
parameters.scope = extenededPermissions;
// Create the login url
Facebook fc = new FacebookClient();
loginUrl = fc.GetLoginUrl(parameters);
}
private void WindowLoaded(object sender, RoutedEventArgs e)
{
// get the login url
GetLoginUrl();
// Navigate to that page
webBrowser.Navigate(loginUrl);
}
private void webBrowser_Navigated(object sender, NavigationEventArgs e)
{
var fc = new FacebookClient();
FacebookOAuthResult fr;
// Check the returned url
if (fc.TryParseOAuthCallbackUrl(e.Uri, out fr))
{
// check if authentication is success or not
if (fr.IsSuccess)
{
getUserName(out userName);
}
else
{
var errorDes = fr.ErrorDescription;
var errorReason = fr.ErrorReason;
}
}
else
{
}
}
private void getUserName(out string name)
{
var fb = new FacebookClient(accessToken);
// Get the user details
dynamic result = fb.Get("me");
// Get the user name
name = result.name;
MessageBox.Show("Hai " + name + ",Welcome to my App");
}
}
My Problem is with the FacebookOAuthResult.
private void webBrowser_Navigated(object sender, NavigationEventArgs e)
{
var fc = new FacebookClient();
FacebookOAuthResult fr;
// Check the returned url
if (fc.TryParseOAuthCallbackUrl(e.Uri, out fr))
{
// check if authentication is success or not
if (fr.IsSuccess)
{
getUserName(out userName);
}
else
{
var errorDes = fr.ErrorDescription;
var errorReason = fr.ErrorReason;
}
}
else
{
}
}
After I logged in it is redirecting to redirect_uri. But the fc.TryParseOAuthCallbackUrl(e.Uri, out fr) fails though the webbrowser redirects to the Authentication successful page.
So I couldn't get the access token. What could the problem in my code be?

Answer 1

This doesn't answer the question, but I see you are asking for an offline_access permission. Facebook removed offline_access sometime ago. Instead you need an Extended Access Token. You get it by exchanging the access token you are trying to get, for an extended one. They last for about 2-3 months after which you have to get a new one.

Answer 2

Nevermind i have found out the solution..Thanks to the answers for the question!
I have added the Winforms web browser control to the wpf and the authentication is working.The problem is with WPF web browser. It simply omits the url after # token So the parseurl won't able to authenticate it.
Here's the modified code..
private void WindowLoaded(object sender, RoutedEventArgs e)
{
// create the windows form host
System.Windows.Forms.Integration.WindowsFormsHost sample =
new System.Windows.Forms.Integration.WindowsFormsHost();
// create a new web browser
webBrowser = new System.Windows.Forms.WebBrowser();
// add it to winforms
sample.Child = webBrowser;
// add it to wpf
canvas1.Children.Add(sample);
webBrowser.Navigated += webBrowser_Navigated;
webBrowser.Navigate(loginURL);
}
void webBrowser_Navigated(object sender, WebBrowserNavigatedEventArgs e)
{
// do the authentication
var fc = new FacebookClient();
FacebookOAuthResult fr;
// Check the returned url
if (fc.TryParseOAuthCallbackUrl(e.Url, out fr))
{
// check if authentication is success or not
if (fr.IsSuccess)
{
accessToken = fr.AccessToken;
// Actions to do
}
else
{
var errordes = fr.ErrorDescription;
var errorreason = fr.ErrorReason;
}
}
else
{
//Not a valid url
}
}
The problem is solved!!