string client_id = "分配的APP ID";
  string appid = " 分配的 APP KEY";
  string Return_url = "返回处理的url";
  public string Authorize()
  {
   string state = new Random(100000).Next(99, 99999).ToString();//随机数
   HttpHelper http = new HttpHelper();
   string url = string.Format("https://graph.qq.com/oauth2.0/authorize?response_type=code&client_id={0}&redirect_uri={1}&state={2}", client_id, Return_url, state);
   string str="<script> location.href='" + url + "'</script>";
   return str;
  
  }

 protected void Page_Load(object sender, EventArgs e)
  { 
   QQ_Login q = new QQ_Login();
   string url = q.Authorize();//这里调用
   Response.Write(url);
  }

  public User_info Back_User(string code)
  {
   string state = new Random(100000).Next(99, 99999).ToString();//随机数
   User_info ui = new User_info();
   string url = string.Format("https://graph.qq.com/oauth2.0/token?grant_type=authorization_code&client_id={0}&client_secret={1}&code={2}&redirect_uri={3}&state={4}", client_id, appid, code, Return_url, state);
   string uu = HttpHelper.HtmlFromUrlGet(url);//处理http请求帮助类
   string code1 = uu.Split('&')[0].Split('=')[1].ToString();//获得access_token
 
   //根基access_token获取用户唯一OpenID
   string url_me = string.Format("https://graph.qq.com/oauth2.0/me?access_token={0}" , code1); 
   string callback = HttpHelper.HtmlFromUrlGet(url_me);//这里获取的
   callback = callback.Substring(callback.IndexOf('(') + 1, (callback.IndexOf(')') - callback.IndexOf('(') - 1)).Trim();
   // dynamic jsonP = JValue.FromObject(callback); //这里我用的是一个序列化类库 Newtonsoft.Json.dll 6.0.4版本无奈公司版本过低 只能用4.0的版本 建议使用6.0.4版本
   a jsonP = JsonConvert.DeserializeObject<a>(callback);//Newtonsoft.Json.dll 4.0或4.5版本
   string OpenID = jsonP.openid;//获取用户唯一的OpenID 
 
   //根据OpenID获取用户信息 可以显示更多 用的就几个 需要的可以自己在下面加
   string getinfo = string.Format("https://graph.qq.com/user/get_user_info?access_token={0}&oauth_consumer_key={1}&openid={2}", code1, client_id, OpenID);
   string user = HttpHelper.HtmlFromUrlGet(getinfo);
   b info = JsonConvert.DeserializeObject<b>(user);
   ui.Name = info.nickname;
   ui.OpenID = OpenID;
   ui.img_qq100 = info.figureurl_qq_1;
   ui.img_qq50 = info.figureurl_qq_2;
   ui.city = info.city;
   ui.year = info.year;
   ui.Type = 1;
   return ui; 
 
  }

User_info ui = new User_info();
     var verifier = Request.Params["code"]; //获取Authorization Code
     ui = q.Back_User(verifier); 掉用方法并返回数据

  public class User_info
  {
   public string OpenID { get; set; }//用户唯一appid
 
   public string Name { get; set; } 
 
   public string img_qq50 { get; set; } //QQ图像40*40
 
   public string img_qq100 { get; set; }
 
   public string city { get; set; }

   public int year { get; set; } 
  }

 public class a {
 
  public string client_id { get; set; }
 
  public string openid { get; set; }
 }