Question

I’ve been using the old v3.0 C# SDK for some time and Facebook have decided to deprecate that API and also block it so I can no longer use it. I’m trying to upgrading to v5.0 but it seems a lot more different and I can’t get it to authenticate.

All I need is a Facebook login button which people click, login and allow permissions to my app (which works) but then I want to be able to call Get() on the C# SDK in the code behind to get their friends. This is what I have in my aspx page which works fine to allow them to login:

<input type="button" id="fblogin" value="Login to Facebook" disabled="disabled"/>
<div id="fb-root"></div>
<script>
window.fbAsyncInit = function() {
    FB.init({
        appId: 'myappid',
        cookie: true,
        xfbml: true,
        oauth: true
    });

    function facebooklogin() {
        FB.login(function(response) {
            if (response.authResponse) {
                // user authorized
                // make sure to set the top.location instead of using 
                var accessToken = response.authResponse.accessToken;
                window.location.reload();
            } else {
                // user cancelled
            }
        },
          {
            scope: 'publish_stream' 
          });
    };

    $(function() {
        // make the button is only enabled after the facebook js sdk has been loaded.
        $('#fblogin').attr('disabled', false).click(facebooklogin);
    });
};
(function() {
    var e = document.createElement('script'); e.async = true;
    e.src = document.location.protocol + '//connect.facebook.net/en_US/all.js';
    document.getElementById('fb-root').appendChild(e);
} ());

However when I’m trying to connect to the Facebook client as below it throws an error which says

(OAuthException) An active access token must be used to query
information about the current user.”} System.Exception
{Facebook.FacebookOAuthException}

FacebookClient client = new FacebookClient(myappid, mysecretkey)
SomeDictionary object = client.Get("/me/friends");

What am I missing to get this active authtoken? How can I access it in the code behind? Also what’s the difference between using FacebookClient and FacebookWebClient?

Answer 1

In your web.config file you also have to set:

<facebookSettings appSecret="your app secret" appId="your app id" />

and to get the current user:

var facebookApp = new FacebookApp();
facebookApp.Api("/4");