c# - how to post to facebook page wall from .NET

Question

I've created Facebook page. I have no application secret and no access token.

I want to post to this page from my .NET desktop application. How can I do it? Can anyone help please, where can I get access token for this?

Should I create a new Facebook Application? If yes, how can I grant permissions to this application to post on page's wall?

UPD1: I have no website. I need to post company's news from .NET desktop application to company's Facebook page. All I have is Login/Password for Facebook Page Account.

UPD2: I've created Facebook Application. With AppID/SecretKey. I can get access token. But... How can I grant permissions to post to page's wall?

(OAuthException) (#200) The user hasn't authorized the application to perform this action

Answer 1

I have created a video tutorial showing how to do this at this location:

http://www.markhagan.me/Samples/Grant-Access-And-Post-As-Facebook-User-ASPNet

You will notice that, in my example, I am asking for both "publish_stream" and "manage_pages". This let's you also post on pages of which that users is an admin. Here is the full code:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using Facebook;

namespace FBO
{
    public partial class facebooksync : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            CheckAuthorization();
        }

        private void CheckAuthorization()
        {
            string app_id = "374961455917802";
            string app_secret = "9153b340ee604f7917fd57c7ab08b3fa";
            string scope = "publish_stream,manage_pages";

            if (Request["code"] == null)
            {
                Response.Redirect(string.Format(
                    "https://graph.facebook.com/oauth/authorize?client_id={0}&redirect_uri={1}&scope={2}",
                    app_id, Request.Url.AbsoluteUri, scope));
            }
            else
            {
                Dictionary<string, string> tokens = new Dictionary<string, string>();

                string url = string.Format("https://graph.facebook.com/oauth/access_token?client_id={0}&redirect_uri={1}&scope={2}&code={3}&client_secret={4}",
                    app_id, Request.Url.AbsoluteUri, scope, Request["code"].ToString(), app_secret);

                HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;

                using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
                {
                    StreamReader reader = new StreamReader(response.GetResponseStream());

                    string vals = reader.ReadToEnd();

                    foreach (string token in vals.Split('&'))
                    {
                        //meh.aspx?token1=steve&token2=jake&...
                        tokens.Add(token.Substring(0, token.IndexOf("=")),
                            token.Substring(token.IndexOf("=") + 1, token.Length - token.IndexOf("=") - 1));
                    }
                }

                string access_token = tokens["access_token"];

                var client = new FacebookClient(access_token);

                client.Post("/me/feed", new { message = "markhagan.me video tutorial" });
            }
        }
    }
}