using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading.Tasks;
using System.Web;

namespace AirMedia.Wap.Core
{
    public static class HttpWebHelper
    {
        /// <SUMMARY>  
        /// httpwebrequest类中的一些属性的集合  
        /// </SUMMARY>  
        public class RequestParam
        {
            /// <SUMMARY>  
            /// 获取或设置request类中的Accept属性  
            /// 用以设置接受的文件类型  
            /// </SUMMARY>              
            public string Accept { get; set; }

            /// <SUMMARY>  
            /// 获取或设置request类中的ContentType属性  
            /// 用以设置请求的媒体类型  
            /// </SUMMARY>            
            public string ContentType { get; set; }

            /// <SUMMARY>  
            /// 获取或设置request类中的UserAgent属性  
            /// 用以设置请求的客户端信息  
            /// </SUMMARY>  
            public string UserAgent { get; set; }

            /// <SUMMARY>  
            /// 获取或设置request类中的Method属性  
            /// 可以将 Method 属性设置为任何 HTTP 1.1 协议谓词：GET、HEAD、POST、PUT、DELETE、TRACE 或 OPTIONS。  
            /// 如果 ContentLength 属性被设置为 -1 以外的任何值，则必须将 Method 属性设置为上载数据的协议属性。  
            /// </SUMMARY>              
            public string Method { get; set; }

            /// <summary>
            /// 发送的数据
            /// </summary>
            public byte[] PostData { get; set; }
        }
        /// <SUMMARY>  
        /// 构建一个httt请求以获取目标链接的cookies,需要传入目标的登录地址和相关的post信息,返回完成登录的cookies,以及返回的html内容  
        /// </SUMMARY>  
        /// <PARAM name="url">登录页面的地址</PARAM>  
        /// <PARAM name="post">post信息</PARAM>  
        /// <PARAM name="strHtml">输出的html代码</PARAM>  
        /// <PARAM name="rppt">请求的标头所需要的相关属性设置</PARAM>  
        /// <RETURNS>请求完成后的cookies</RETURNS>  
        public static CookieCollection GetCookie(string url, RequestParam rppt, out string strHtml)
        {

            CookieCollection ckclReturn = new CookieCollection();
            CookieContainer cc = new CookieContainer();
            HttpWebRequest hwRequest;
            HttpWebResponse hwResponse;
            Stream stream;

            hwRequest = (HttpWebRequest)HttpWebRequest.Create(new Uri(url));
            hwRequest.CookieContainer = cc;
            if (rppt != null)
            {
                hwRequest.Accept = rppt.Accept;
                hwRequest.ContentType = rppt.ContentType;
                hwRequest.UserAgent = rppt.UserAgent;
                hwRequest.Method = rppt.Method;
                hwRequest.ContentLength = rppt.PostData.Length;
                //写入标头  

                stream = hwRequest.GetRequestStream();
                stream.Write(rppt.PostData, 0, rppt.PostData.Length);
                stream.Close();
            }
            //发送请求获取响应内容  
            try
            {
                hwResponse = (HttpWebResponse)hwRequest.GetResponse();
            }
            catch
            {
                strHtml = "";
                return ckclReturn;
            }
            stream = hwResponse.GetResponseStream();
            StreamReader sReader = new StreamReader(stream, Encoding.UTF8);
            strHtml = sReader.ReadToEnd();
            sReader.Close();
            stream.Close();
            //获取缓存内容  
            ckclReturn = hwResponse.Cookies;
            return ckclReturn;
        }

        /// <SUMMARY>  
        /// 根据已经获取的有效cookies来获取目标链接的内容  
        /// </SUMMARY>  
        /// <PARAM name="strUri">目标链接的url</PARAM>  
        ///<PARAM name="post">post的byte信息</PARAM>  
        /// <PARAM name="ccl">已经获取到的有效cookies</PARAM>  
        /// <PARAM name="rppt">头属性的相关设置</PARAM>  
        /// <RETURNS>目标连接的纯文本:"txt/html"</RETURNS>  
        public static string GetHtmlByCookies(string strUri, byte[] post, CookieCollection ccl, RequestParam rppt)
        {
            CookieContainer cc = new CookieContainer();
            HttpWebRequest hwRequest;
            HttpWebResponse hwResponse;

            //构建即将发送的包头         
            hwRequest = (HttpWebRequest)HttpWebRequest.Create(new Uri(strUri));
            cc.Add(ccl);
            hwRequest.CookieContainer = cc;
            hwRequest.Accept = rppt.Accept;
            hwRequest.ContentType = rppt.ContentType;
            hwRequest.UserAgent = rppt.UserAgent;
            hwRequest.Method = rppt.Method;
            hwRequest.ContentLength = post.Length;
            //写入post信息  
            Stream stream;
            stream = hwRequest.GetRequestStream();
            stream.Write(post, 0, post.Length);
            stream.Close();
            //发送请求获取响应内容  
            try
            {
                hwResponse = (HttpWebResponse)hwRequest.GetResponse();
            }
            catch
            {
                return "";
            }

            stream = hwResponse.GetResponseStream();
            StreamReader sReader = new StreamReader(stream, Encoding.Default);
            string strHtml = sReader.ReadToEnd();
            sReader.Close();
            stream.Close();

            //返回值            
            return strHtml;
        }


        /// <summary>  
        /// 根据泛型来构建字符串用于post  
        /// </summary>  
        /// <param name="dir">带有键值对的泛型</param>  
        /// <returns>构建完毕的字符串</returns>  
        public static byte[] CreatePostData(Dictionary<string, string> dir)
        {
            StringBuilder strPost = new StringBuilder();
            foreach (KeyValuePair<string, string> kvp in dir)
            {
                strPost.Append(kvp.Key);
                strPost.Append('=');
                if (!string.IsNullOrWhiteSpace(kvp.Value))
                {
                    strPost.Append(System.Web.HttpUtility.UrlEncode(kvp.Value));
                }
                strPost.Append('&');
            }
            return CreatePostData(strPost.ToString().TrimEnd('&'));
        }

        public static byte[] CreatePostData(string input)
        {
            return Encoding.Default.GetBytes(input);
        }

        /// <summary>
        /// 向指定uri发起GET请求
        /// </summary>
        /// <param name="uri"></param>
        /// <param name="request"></param>
        /// <returns></returns>
        public static string GET(string url)
        {
            WebClient wc = new WebClient();
            wc.Encoding = System.Text.Encoding.UTF8;
            string s = wc.DownloadString(url);
            s = HttpUtility.UrlDecode(s);
            return s;
        }
    }

    /// <summary>  
    /// 有关HTTP请求的辅助类  
    /// </summary>  
    public class HttpWebResponseUtility
    {
        private static readonly string DefaultUserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
        /// <summary>  
        /// 创建GET方式的HTTP请求  
        /// </summary>  
        /// <param name="url">请求的URL</param>  
        /// <param name="timeout">请求的超时时间</param>  
        /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>  
        /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>  
        /// <returns></returns>  
        public static HttpWebResponse CreateGetHttpResponse(string url, IDictionary<string, string> parameters, int? timeout, string userAgent, Encoding requestEncoding, CookieCollection cookies)
        {
            if (string.IsNullOrEmpty(url))
            {
                throw new ArgumentNullException("url");
            }
            StringBuilder buffer = new StringBuilder();
            if (!(parameters == null || parameters.Count == 0))
            {

                int i = 0;
                foreach (string key in parameters.Keys)
                {
                    if (i > 0)
                    {
                        buffer.AppendFormat("&{0}={1}", key, parameters[key]);
                    }
                    else
                    {
                        buffer.AppendFormat("{0}={1}", key, parameters[key]);
                    }
                    i++;
                }
            }

            if (buffer.Length > 1)
            {
                url = url + "?" + buffer.ToString();
            }
            url = HttpUtility.UrlDecode(url);
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "GET";
            request.UserAgent = DefaultUserAgent;
            if (!string.IsNullOrEmpty(userAgent))
            {
                request.UserAgent = userAgent;
            }
            if (timeout.HasValue)
            {
                request.Timeout = timeout.Value;
            }
            if (cookies != null)
            {
                request.CookieContainer = new CookieContainer();
                request.CookieContainer.Add(cookies);
            }
            return request.GetResponse() as HttpWebResponse;
        }
        /// <summary>  
        /// 创建POST方式的HTTP请求  
        /// </summary>  
        /// <param name="url">请求的URL</param>  
        /// <param name="parameters">随同请求POST的参数名称及参数值字典</param>  
        /// <param name="timeout">请求的超时时间</param>  
        /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>  
        /// <param name="requestEncoding">发送HTTP请求时所用的编码</param>  
        /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>  
        /// <returns></returns>  
        public static HttpWebResponse CreatePostHttpResponse(string url, IDictionary<string, string> parameters, int? timeout, string userAgent, Encoding requestEncoding, CookieCollection cookies)
        {
            if (string.IsNullOrEmpty(url))
            {
                throw new ArgumentNullException("url");
            }
            if (requestEncoding == null)
            {
                throw new ArgumentNullException("requestEncoding");
            }
            HttpWebRequest request = null;
            //如果是发送HTTPS请求  
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
                request = WebRequest.Create(url) as HttpWebRequest;
                request.ProtocolVersion = HttpVersion.Version10;
            }
            else
            {
                request = WebRequest.Create(url) as HttpWebRequest;
            }
            request.Method = "POST";
            // request.ContentType = "application/x-www-form-urlencoded";
            request.ContentType = "application/json";
            if (!string.IsNullOrEmpty(userAgent))
            {
                request.UserAgent = userAgent;
            }
            else
            {
                request.UserAgent = DefaultUserAgent;
            }

            if (timeout.HasValue)
            {
                request.Timeout = timeout.Value;
            }
            if (cookies != null)
            {
                request.CookieContainer = new CookieContainer();
                request.CookieContainer.Add(cookies);
            }
            //如果需要POST数据  
            if (!(parameters == null || parameters.Count == 0))
            {
                StringBuilder buffer = new StringBuilder();
                int i = 0;
                foreach (string key in parameters.Keys)
                {
                    if (i > 0)
                    {
                        buffer.AppendFormat("&{0}={1}", key, parameters[key]);
                    }
                    else
                    {
                        buffer.AppendFormat("{0}={1}", key, parameters[key]);
                    }
                    i++;
                }
                byte[] data = http://www.mamicode.com/requestEncoding.GetBytes(buffer.ToString());>

调用
string requestUrl = CoreInterface.ApiDomain + "api/Login/AddQRLog?grid={0}&ad={1}&grName={2}&vc={3}&br={4}&sc={5}&ts={6}&ps={7}";
            requestUrl = string.Format(requestUrl, grid, ad, grName, vc, br, sc, ts, ps);
            string resultJson = "";
            //try
            //{
                HttpWebResponse response = HttpWebResponseUtility.CreateGetHttpResponse(requestUrl, null, 1000000, "", null, null);
                System.IO.StreamReader sr = new System.IO.StreamReader(response.GetResponseStream());
                resultJson = sr.ReadToEnd();
                sr.Close();
            //}
            //catch (Exception)
            //{
            //    return RedirectToAction("Index", "Error");
            //}

 
C# 自带JSON转换类
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.Serialization.Json;

namespace AirMedia.Wap.Core
{
    public static class JsonHelper
    {
        #region DataContractJsonSerializer

        /// <summary>
        /// 对象转换成json
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="jsonObject">需要格式化的对象</param>
        /// <returns>Json字符串</returns>
        public static string DataContractJsonSerialize<T>(T jsonObject)
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
            string json = null;
            using (MemoryStream ms = new MemoryStream()) //定义一个stream用来存发序列化之后的内容
            {
                serializer.WriteObject(ms, jsonObject);
                json = Encoding.UTF8.GetString(ms.GetBuffer()); //将stream读取成一个字符串形式的数据，并且返回
                ms.Close();
            }
            return json;
        }

        /// <summary>
        /// json字符串转换成对象
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="json">要转换成对象的json字符串</param>
        /// <returns></returns>
        public static T DataContractJsonDeserialize<T>(string json)
        {
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
            T obj = default(T);
            using (MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(json)))
            {
                obj = (T)serializer.ReadObject(ms);
                ms.Close();
            }
            return obj;
        }

        #endregion
    }
}