public string GetFaceBookEmail()
        {
            string email = "";
            try
            {
                string token = Request.QueryString["FaceBooktoken"];
                if (token != string.Empty && token != null)
                {
                    string HitURL = string.Format("https://graph.facebook.com/me?access_token={0}", token);
                    oAuthFacebooks objFbCall = new oAuthFacebooks();
                    string JSONInfo = objFbCall.WebRequest(oAuthFacebooks.Method.GET, HitURL, "");

                    var objJson = JsonValue.Parse(JSONInfo);
                    if (objJson.Count > 0)
                    {
                        email = JsonParser.getString(objJson, "email");
                        string firstname = JsonParser.getString(objJson, "first_name");
                        string link = JsonParser.getString(objJson, "link");
                        string username = JsonParser.getString(objJson, "username");
                        string gender = JsonParser.getString(objJson, "gender");
                        string lastname = JsonParser.getString(objJson, "last_name");
                        FirstName = firstname;
                        LastName = lastname;
                        lblAlertMsg.Text = firstname + "Sucessfully Logged In with FaceBook  and the email Address is " + email;
                    }
                }
            }
            catch (Exception exception)
            {
                ProcessException(exception);
            }
            Session.Remove(SessionKeys.ServiceProvider);
            return email;
        }
 public void CheckFaceBook()
 {
     string redirect = HttpContext.Current.Request.Url.ToString().Split('?')[0];
     if (Request.QueryString["code"] != null)
     {
         string code = Request.QueryString["code"].ToString();
         oAuthFacebooks fbAC = new oAuthFacebooks(); //Standard FB class file available on net in c#
         string respnse = "";
         try
         {
             fbAC.AccessTokenGet(code, redirect);
             respnse = fbAC.Token;
         }
         catch (Exception exception)
         {
             ProcessException(exception);
         }
         Response.Redirect(redirect + "?FaceBooktoken=" + respnse);
     }
 }