How to post on facebook page?

[Snowjim]

Hi, I have created a facebook page and a facebook application for my ASP.NET website and now I need to post messages from my ASP.NET webpage onto the facebook page with help of facebook SDK .NET. This is what I got so far :

public static bool UploadPost(string message)
{
dynamic result;

    //https://developers.facebook.com/tools/explorer/
    //https://developers.facebook.com/tools/access\_token/
    FacebookClient client = new FacebookClient("secret access token");


    result = client.Get("oauth/access\_token", new
        {
            client\_id = "\[Client ID number\]",
            client\_secret = "\[Client sercret",
            grant\_type = "client\_credentials",
        });

    result = client.Post("\[facebook app Id\]/feed", new { message = "Test Message from app" });
    //result.id;
    result = client.Get("\[facebook app Id\]");

    return false;
}

When running this I get(on client.Post) :

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

If I remove the client.Post row every thing works good, the correct data is fetched. I have tried follow some helps on facebook SDK .NET website but it is still not working. Pleas help