public class VKontakteScopedClient : IAuthenticationClient
    {
        private string appId;
        private string appSecret;

      

        private const string baseUrl = "https://oauth.vk.com/authorize?client_id=";
        private const string graphApiToken= "https://oauth.vk.com/access_token?client_id=";
        private const string graphApiMe = "https://api.vk.com/method/";

      

        public VKontakteScopedClient(string appId, string appSecret)
        {
            this.appId = appId;
            this.appSecret = appSecret;
        }

        public string ProviderName
        {
            get { return "VKontakte"; }
        }

        public void RequestAuthentication(System.Web.HttpContextBase context, Uri returnUrl)
        {
            string url = baseUrl + appId + "&redirect_uri=" + HttpUtility.UrlEncode(returnUrl.ToString()) + "&response_type=code";
            context.Response.Redirect(url);

           
        }

        public AuthenticationResult VerifyAuthentication(System.Web.HttpContextBase context)
        {
            string code = context.Request.QueryString["code"];

            string rawUrl = context.Request.Url.OriginalString;
            //From this we need to remove code portion
            rawUrl = Regex.Replace(rawUrl, "&code=[^&]*", "");

            IDictionary<string, string> userData = GetUserData(code, rawUrl);

            if (userData == null)
                return new AuthenticationResult(false, ProviderName, null, null, null);

            string id = userData["id"];
            //string username = userData["username"];
            //userData.Remove("id");
            //userData.Remove("username");

            AuthenticationResult result = new AuthenticationResult(true, ProviderName, id, userData["email"], userData);
            return result;
        }
        private static string GetHTML(string URL)
        {
            string connectionString = URL;

            try
            {
                System.Net.HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(connectionString);
                myRequest.Credentials = CredentialCache.DefaultCredentials;
                //// Get the response
                WebResponse webResponse = myRequest.GetResponse();
                Stream respStream = webResponse.GetResponseStream();
                ////
                StreamReader ioStream = new StreamReader(respStream);
                string pageContent = ioStream.ReadToEnd();
                //// Close streams
                ioStream.Close();
                respStream.Close();
                return pageContent;
            }
            catch (Exception er)
            {
                string e = er.Message;
            }
            return null;
        }

        private IDictionary<string, string> GetUserData(string accessCode, string redirectURI)
        {
            string token = GetHTML(graphApiToken + appId + "&redirect_uri=" + HttpUtility.UrlEncode(redirectURI) + "&client_secret=" + appSecret + "&code=" + accessCode);
            if (token == null || token == "")
            {
                return null;
            }

            /* fields
             * перечисленные через запятую поля анкет, 
             * необходимые для получения. Доступные значения: 
             * uid, first_name, last_name, nickname, screen_name,
             * sex, bdate (birthdate), city, country, timezone, 
             * photo, photo_medium, photo_big, has_mobile, rate, 
             * contacts, education, online, counters.
             */

            Dictionary<string, string> AccessTokenParam = JsonConvert.DeserializeObject<Dictionary<string, string>>(token);
            string data = GetHTML(string.Format("{0}getProfiles?uid={1}&access_token={2}&fields=sex,bdate,nickname,screen_name,city,photo,contacts", graphApiMe, AccessTokenParam["user_id"], AccessTokenParam["access_token"]));
            //// this dictionary must contains
            var userData = JsonConvert.DeserializeObject(data);
            VKontakteResponce vkr = JsonConvert.DeserializeObject<VKontakteResponce>(data);
            return (vkr.VKontakteUserArray.GetValue(0) as VKontakteUser).VKontakteUserData;
        }
       
    }

     [JsonObject]
    public class VKontakteResponce
    {
         public VKontakteResponce ()
         {
             VKontakteUserArray = new VKontakteUser [1];
         }

         [JsonProperty("response")]
         public VKontakteUser[] VKontakteUserArray
         {
             get;
             set;
         }
    }


   
    [JsonObject]
    public class VKontakteUser : Dictionary<string,string>
    {
        
        [JsonProperty("uid")]
        public int uid {get; set;}
        [JsonProperty("first_name")]
        public string first_name {get;set;}
        [JsonProperty("last_name")]
        public string last_name {get;set;}
        [JsonProperty("sex")]
        public string sex { get; set; }
        [JsonProperty("bdate")]
        public string bdate { get; set; }
        [JsonProperty("nickname")]
        public string nickname { get; set; }
        [JsonProperty("screen_name")]
        public string screen_name { get; set; }
        [JsonProperty("city")]
        public string city { get; set; }
        [JsonProperty("photo")]
        public string photo { get; set; }
        [JsonProperty("contacts")]
        public string contacts { get; set; }

        public IDictionary<string, string> VKontakteUserData
        {

         

            get
            {
                Dictionary<string, string> dict = new Dictionary<string, string>();

                dict.Add(SSOUserPropertiesEnum.id.ToString(), uid.ToString());
                dict.Add(SSOUserPropertiesEnum.first_name.ToString(),first_name);
                dict.Add(SSOUserPropertiesEnum.last_name.ToString(), last_name);
                dict.Add(SSOUserPropertiesEnum.gender.ToString(), sex);
                dict.Add(SSOUserPropertiesEnum.birthday.ToString(), bdate);
                dict.Add(SSOUserPropertiesEnum.email.ToString(), contacts);
                return dict;
            }
        }
    }