上传图片的格式一定要按规定的写，不然没办法正确上传的。
我在上传的时候就是值前面没有空一行，导致上传不成功，很纠结的错误。
我要模拟的是一个FLASH的上传控件，我开始用HttpAnalyze抓包是抓不到的。后来上网搜索到了【抓包工具】Charles v3.6.4，下载安装后，可以抓到FLASH上传时候的包了。
FLASH上传应该也是POST，可能不是HTTP包，但应该可以按HTTP的方式发送吧。结果证明我的想法是对的，可以正常上传。
FLASH上传与普通的按钮上传控件有什么区别呢？有待搜索到相关资料。
Charles v3.6.4 下载地址
原版下载地址: http://www.charlesproxy.com/download/
破解补丁下载地址: http://note.sdo.com/u/1528563206/n/r70o6~jK35opnM10I000fd
下面是参考代码，注意上传的格式就好。
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","123456"); 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" * * 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 * * <这里是1.txt文件的内容> * --7d4a6d158c9 * * 请注意，每一行都必须以 结束value前面必须有2个 ，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", "7766517")); 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(" "); sb.Append("Content-Disposition: form-data; name="" + dicItem.Key + """); sb.Append(" "); sb.Append(" "); sb.Append(dicItem.Value);//value前面必须有2个换行 sb.Append(" "); } //拼接文件控件 sb.Append("--"+boundary); sb.Append(" "); sb.Append("Content-Disposition: form-data; name="file1"; filename="C:\upload" + Path.GetFileName(fileName) + """); sb.Append(" "); sb.Append("Content-Type: application/octet-stream"); sb.Append(" "); sb.Append(" ");//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(" --" + boundary + " "); //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, 0, postHeaderBytes.Length); // Write out the file contents 将附件写入流,最大4M byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)fileStream.Length))]; int bytesRead = 0; while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0) requestStream.Write(buffer, 0, bytesRead); fileStream.Dispose(); // Write out the trailing boundary 将结束标记写入流 requestStream.Write(boundaryBytes, 0, 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[4096];//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, 0, buffer1.Length); if (l > 0) { fileStream.Write(buffer1, 0, l);//将文件流按字节写入内存流 } } while (l > 0); stream1.Close(); fileStream.Position = 0; 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 = 0; while (sLine != null) { i++; sLine = objReader.ReadLine(); if (sLine != null) HTML += sLine; } HTML = HTML.Replace("<", "<"); HTML = HTML.Replace(">", ">"); objReader.Dispose(); return HTML; } #endregion } }