using System; 
 
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.IO;
using System.Web;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {
            CSDN cs = new CSDN();

            if (cs.Login("qq578023708", "*************"))  cs.Reply("390521782","帮你顶了，一定要给分哦！"); //390521782为帖子ID
            Console.ReadLine();
        }
    }
    
    class CSDN {   
        HttpWebRequest httpq = null;
        HttpWebResponse httpp = null;
        CookieCollection cc = null;
        string cook = null;
        /// <summary>
        /// 登陆
        /// </summary>
        /// <param name="userName">用户名</param>
        /// <param name="pwd">密码</param>
        /// <returns>返回TRUE 成功 返回 FALSE 失败</returns>
        public bool Login(string userName, string pwd) {
            httpq =(HttpWebRequest) WebRequest.Create("https://passport.csdn.net/ajax/accounthandler.ashx?t=log&u="+userName+"&p="+pwd+"&remember=0&f=http%3A%2F%2Fbbs.csdn.net%2Ftopics%2F390521782&rand=0.5834313757092409");
            httpq.Accept = "*/*";
            httpq.Referer = "https://passport.csdn.net/account/loginbox?callback=logined&hidethird=1&from=http%3a%2f%2fbbs.csdn.net%2ftopics%2f390521782";
            httpq.CookieContainer = new CookieContainer();
            httpp =(HttpWebResponse) httpq.GetResponse(); 
 
            httpp.Cookies = cc;
            StreamReader sr = new StreamReader(httpp.GetResponseStream());
            cook = httpp.Headers["set-cookie"];
            string re = sr.ReadToEnd();
            if (re.IndexOf("\"status\":true") != -1) return true;
            else return false;
            
        }
        /// <summary>
        /// 回帖
        /// </summary>
        /// <param name="id">帖子ID</param>
        /// <param name="text">回帖内容</param>
        /// <returns></returns>
        public string Reply(string id,string text) {
            httpq = (HttpWebRequest)WebRequest.Create("http://bbs.csdn.net/topics/"+id+"?page=1");
            httpq.Accept = "application/json, text/javascript, */*";
            httpq.Referer = "http://bbs.csdn.net/topics/"+id+"?page=1";
            StreamReader ssr = new StreamReader( httpq.GetResponse().GetResponseStream());
            string RR = ssr.ReadToEnd();
            int index1= RR.IndexOf("csrf-param");
            int index2 = RR.IndexOf("content", index1);
            index2 += 9;
            index1 = RR.IndexOf(" ", index2)-1;
            string token= RR.Substring(index2, index1 - index2);
            httpq = (HttpWebRequest)WebRequest.Create("http://bbs.csdn.net/posts?topic_id="+id); 
 
            httpq.Referer = "http://bbs.csdn.net/topics/" + id + "?page=1";
            httpq.Accept = "application/json, text/javascript, */*";
            foreach (Cookie co in cc) {
                httpq.CookieContainer.Add(co);
            }
            httpq.Method = "post";
            httpq.ContentType = "application/x-www-form-urlencoded";
            byte[] bytes = Encoding.UTF8.GetBytes("utf8=%E2%9C%93&authenticity_token="+HttpUtility.UrlEncode(token)+"&post%5Bbody%5D="+HttpUtility.UrlEncode(text)+"&commit=%E6%8F%90%E4%BA%A4%E5%9B%9E%E5%A4%8D");
            httpq.ContentLength = bytes.Length;
            httpq.GetRequestStream().Write(bytes, 0, bytes.Length);
            httpp =(HttpWebResponse) httpq.GetResponse();
            StreamReader sr = new StreamReader(httpp.GetResponseStream());
            return sr.ReadToEnd();

        }
    }
}