Get access token to facebook page - WPF

debugcn Published at Dev

Marcos Anderson

I am developing a WPF application that needs post on wall of a facebook's Page, and this without login window. Well, I want to get access token for my facebook page, and this is my code.

        var fb = new FacebookClient();
        string token = "";
        dynamic accounts = fb.Get("/"<USER_ID>"/accounts");
        foreach (dynamic account in accounts)
        {
            if (account.id == <PAGE_ID>)
            {
                token = account.access_token;
                break;
            }
        }

But I receive a error #104. It is a simple error, that I need a access token to do this operation. Then I use other code to get the user access token

        var fb = new FacebookClient();
        dynamic result = fb.Get("oauth/access_token", new
        {
            client_id = <PAGE_ID>,
            client_secret = <APP_SECRET>,
            grant_type = "fb_exchange_token",
            fb_exchange_token = <USER_TOKEN>
        });

But I get error #101:

"Error validating application. Cannot get application info due to a system error."

Someone knows what I have to do?

Thanks!!!

Sahil Mittal

I'm not sure if you've been able to get a never expiring token for the page, so I'll explain you the steps:

Open Graph API Explorer
Select your app from the drop-down
Click "Get Access Token" button, and select the manage_pages permission.

Copy the token and run this in the browser:

 https://graph.facebook.com/oauth/access_token?grant_type=fb_exchange_token&client_id={app-id}&client_secret={app-secret}&fb_exchange_token={step-3-token}

Copy the token from step-4 and paste in to the access_token field and call:
```
 /{page-id}?fields=access_token
```
The token you get now is a never-expiring token, you can validate the same in Debugger .Use this in your app.