利用HttpWebRequest模拟表单提交

using System;
using System.Collections.Specialized;
using System.IO;
using System.Net;
using System.Text;

namespace Allyn.Common
{
    public class HttpHelper
    {
        /// <summary>
        /// 获取指定路径数据
        /// </summary>
        /// <param name="requestUri">提交路径</param>
        /// <param name="cookie">Cookie容器对象</param>
        /// <returns>字符串结果</returns>
        public static string GetForm(string requestUri, CookieContainer cookie)
        {
            HttpWebRequest request = WebRequest.CreateHttp(requestUri);
            request.Method = "get";
            request.CookieContainer = cookie;
            request.ContentLength = 0;

            WebResponse response = request.GetResponse();
            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
            return reader.ReadToEnd();
        }

        /// <summary>
        /// 默认表单提交
        /// </summary>
        /// <param name="requestUri">提交路径</param>
        /// <param name="postData">提交数据</param>
        /// <param name="cookie">Cookie容器对象</param>
        /// <returns>字符串结果</returns>
        public static string PostForm(string requestUri, NameValueCollection postData, CookieContainer cookie)
        {
            HttpWebRequest request = WebRequest.CreateHttp(requestUri);
            request.Method = "post";
            request.ContentType = "application/x-www-form-urlencoded";
            request.CookieContainer = cookie;

            StringBuilder stringBuilder = new StringBuilder();
            foreach (string key in postData.Keys)
            {
                stringBuilder.AppendFormat("&{0}={1}", key, postData.Get(key));
            }
            byte[] buffer = Encoding.UTF8.GetBytes(stringBuilder.ToString().Trim('&'));
            Stream requestStream = request.GetRequestStream();
            requestStream.Write(buffer, 0, buffer.Length);
            requestStream.Close();

            WebResponse response = request.GetResponse();
            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
            return reader.ReadToEnd();
        }

        /// <summary>
        /// 多部件表单提交
        /// </summary>
        /// <param name="requestUri">提交路径</param>
        /// <param name="postData">提交数据.注:如果是文件路径,代表是文件.</param>
        /// <param name="cookie">Cookie容器对象</param>
        /// <returns>字符串结果</returns>
        public static string PostFormMultipart(string requestUri, NameValueCollection postData, CookieContainer cookie)
        {
            string boundary = string.Format("-----{0}", DateTime.Now.Ticks.ToString("x"));
            HttpWebRequest webrequest = WebRequest.CreateHttp(requestUri);
            webrequest.CookieContainer = cookie;
            webrequest.Timeout = 120000;
            webrequest.Method = "post";
            webrequest.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);

            Stream requestStream = webrequest.GetRequestStream();
            foreach (string key in postData.Keys)
            {
                StringBuilder strBuilder = new StringBuilder();
                strBuilder.AppendFormat("--{0}", boundary);
                strBuilder.AppendFormat("
Content-Disposition: form-data; name="{0}"", key);
                if (File.Exists(postData.Get(key)))
                {
                    strBuilder.AppendFormat(";filename="{0}"
Content-Type: multipart/form-data

", Path.GetFileName(postData.Get(key)));
                    byte[] buffer = Encoding.UTF8.GetBytes(strBuilder.ToString());
                    requestStream.Write(buffer, 0, buffer.Length);
                    //获取图片流
                    FileStream fileStream = new FileStream(postData.Get(key), FileMode.Open, FileAccess.Read);
                    BinaryReader binaryReader = new BinaryReader(fileStream);
                    byte[] fileBuffer = binaryReader.ReadBytes((int)fileStream.Length);
                    binaryReader.Close();
                    fileStream.Close();
                    requestStream.Write(fileBuffer, 0, fileBuffer.Length);
                }
                else
                {
                    strBuilder.AppendFormat("

{0}
", postData.Get(key));
                    byte[] buff = Encoding.UTF8.GetBytes(strBuilder.ToString());
                    requestStream.Write(buff, 0, buff.Length);
                }
            }

            byte[] boundaryBuffer = Encoding.UTF8.GetBytes(string.Format("
--{0}
", boundary));
            requestStream.Write(boundaryBuffer, 0, boundaryBuffer.Length);
            requestStream.Close();

            WebResponse response = webrequest.GetResponse();
            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
            return reader.ReadToEnd();
        }
    }
}