using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Net;

using System.IO;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

            Dictionary<string, string> inputDic=new Dictionary<string,string>();

            inputDic.Add("username","westfruit");

            inputDic.Add("password","");

            PostFile("http://avatar.csdn.net/0/1/1/1_zfrong.jpg", "http://www.westfruit.com/news/uppic.asp?strAction=shangchuan", @"D:\1.jpg", "application/octet-stream", inputDic);

        }  

        #region 下载文件并上传到指定页面

        /**

         * 如果要在客户端向服务器上传文件，我们就必须模拟一个POST multipart/form-data类型的请求

         * Content-Type必须是multipart/form-data。

         * 以multipart/form-data编码的POST请求格式与application/x-www-form-urlencoded完全不同

         * multipart/form-data需要首先在HTTP请求头设置一个分隔符,例如7d4a6d158c9：

         * 我们模拟的提交要设定 content-type不同于非含附件的post时候的content-type

         * 这里需要： ("Content-Type", "multipart/form-data; boundary=ABCD");

         * 然后，将每个字段用“--7d4a6d158c9”分隔，最后一个“--7d4a6d158c9--”表示结束。

         * 例如，要上传一个title字段"Today"和一个文件C:\1.txt，HTTP正文如下：

         *

         * --7d4a6d158c9

         * Content-Disposition: form-data; name="title"

         * \r\n\r\n

         * Today

         * --7d4a6d158c9

         * Content-Disposition: form-data; name="1.txt"; filename="C:\1.txt"

         * Content-Type: text/plain

         * 如果是图片Content-Type: application/octet-stream

         * \r\n\r\n

         * <这里是1.txt文件的内容>

         * --7d4a6d158c9

         * \r\n

         * 请注意，每一行都必须以\r\n结束value前面必须有2个\r\n，包括最后一行。

        */

        /// <summary>

        /// 下载文件上传到指定地址

        /// </summary>

        /// <param name="getUrl">文件下载地址</param>

        /// <param name="postUrl">文件上传地址</param>

        /// <param name="fileName">file控件名称</param>

        /// <param name="fileType">上传文件类型</param>

        /// <param name="inputParamter">其他表单元素</param>

        public static void PostFile(string getUrl, string postUrl, string fileName, string fileType, Dictionary<string, string> inputDic)

        {  

            CredentialCache cache = new CredentialCache();//创建缓存容器

            cache.Add(new Uri("http://www.westfruit.com/"), "Basic", new NetworkCredential("westfruit", ""));

            CookieContainer cookies = new CookieContainer();//创建cookie容器

            MemoryStream fileStream = GetFileStream(getUrl);//下载文件返回内存流

            // cast the WebRequest to a HttpWebRequest since we're using HTTPS

            string boundary = "----------" + DateTime.Now.Ticks.ToString("x");//元素分割标记

            HttpWebRequest httpWebRequest2 = (HttpWebRequest)WebRequest.Create(postUrl);

            httpWebRequest2.Credentials = cache;

            httpWebRequest2.CookieContainer = cookies;

            httpWebRequest2.ContentType = "multipart/form-data; boundary=" + boundary;//其他地方的boundary要比这里多--

            httpWebRequest2.Method = "POST";//Post请求方式

            // Build up the post message 拼接创建表单内容

            StringBuilder sb = new StringBuilder();

            //拼接非文件表单控件

            //遍历字典取出表单普通空间的健和值

            foreach (KeyValuePair<string, string> dicItem in inputDic)

            {

                sb.Append("--" + boundary);

                sb.Append("\r\n");

                sb.Append("Content-Disposition: form-data; name=\"" + dicItem.Key + "\"");

                sb.Append("\r\n");

                sb.Append("\r\n");

                sb.Append(dicItem.Value);//value前面必须有2个换行

                sb.Append("\r\n");

            }

            //拼接文件控件

            sb.Append("--"+boundary);

            sb.Append("\r\n");

            sb.Append("Content-Disposition: form-data; name=\"file1\"; filename=\"C:\\upload" + Path.GetFileName(fileName) + "\"");

            sb.Append("\r\n");

            sb.Append("Content-Type: application/octet-stream");

            sb.Append("\r\n");

            sb.Append("\r\n");//value前面必须有2个换行

            byte[] postHeaderBytes = Encoding.UTF8.GetBytes(sb.ToString());

            // Build the trailing boundary string as a byte array 创建结束标记

            // ensuring the boundary appears on a line by itself

            byte[] boundaryBytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

            //http请求总长度

            httpWebRequest2.ContentLength = postHeaderBytes.Length + fileStream.Length + boundaryBytes.Length;

            Stream requestStream = httpWebRequest2.GetRequestStream(); //定义一个http请求流

            // Write out our post header 将开始标记写入流

            requestStream.Write(postHeaderBytes, , postHeaderBytes.Length);

            // Write out the file contents 将附件写入流,最大4M

            byte[] buffer = new Byte[checked((uint)Math.Min(, (int)fileStream.Length))];

            int bytesRead = ;

            while ((bytesRead = fileStream.Read(buffer, , buffer.Length)) != )

                requestStream.Write(buffer, , bytesRead);

            fileStream.Dispose();

            // Write out the trailing boundary 将结束标记写入流

            requestStream.Write(boundaryBytes, , boundaryBytes.Length);

            //Send http request back WebResponse 发送http请求

            WebResponse webResponse2 = httpWebRequest2.GetResponse();

            //从WebResponse中解析出html代码开始

            Stream htmlStream = webResponse2.GetResponseStream();

            string HTML = GetHtml(htmlStream, "UTF-8");

            htmlStream.Dispose();

            //从WebResponse中解析出html代码结束

        }

        #endregion

        #region 下载文件

        /// <summary>

        /// 从互联网下载文件

        /// </summary>

        /// <param name="getUrl">文件地址</param>

        /// <returns>内存流</returns>

        public static MemoryStream GetFileStream(string getUrl)

        {

            MemoryStream fileStream;//定义一个内存流保存接收到的文件流

            HttpWebRequest httpWebRequest1 = (HttpWebRequest)WebRequest.Create(getUrl);

            WebResponse webResponse1 = httpWebRequest1.GetResponse();

            byte[] buffer1 = new byte[];//定义一个4M大小的数字

            Stream stream1 = webResponse1.GetResponseStream();//定义一个流接受html返回的文件流

            fileStream = new MemoryStream();//stream1不支持查找操作所以将其转入内存流

            int l;

            do

            {

                l = stream1.Read(buffer1, , buffer1.Length);

                if (l > )

                {

                    fileStream.Write(buffer1, , l);//将文件流按字节写入内存流

                }

            }

            while (l > );

            stream1.Close();

            fileStream.Position = ;

            return fileStream;

        }

        #endregion

        #region 解析html代码

        /// <summary>

        /// 从html流中解析出html代码

        /// </summary>

        /// <param name="htmlStream">html流</param>

        /// <param name="Encoding">编码格式</param>

        /// <returns>html</returns>

        public static string GetHtml(Stream htmlStream, string Encoding)

        {

            StreamReader objReader = new StreamReader(htmlStream, System.Text.Encoding.GetEncoding(Encoding));

            string HTML = "";

            string sLine = "";

            int i = ;

            while (sLine != null)

            {

                i++;

                sLine = objReader.ReadLine();

                if (sLine != null)

                    HTML += sLine;

            }

            HTML = HTML.Replace("<", "<");

            HTML = HTML.Replace(">", ">");

            objReader.Dispose();

            return HTML;

        }

        #endregion

    }

}