使用HttpWebRequest提交ASP.NET表单并保持Session和Cookie

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;

namespace WinTest
{
    /// <summary>
    /// 通过程序自动填充并提交ASP.NET表单(Form)
    /// </summary>
    public partial class AutoPost : Form
    {
        public AutoPost()
        {
            InitializeComponent();
        }

        private void AutoPost_Load(object sender, EventArgs e)
        {
        }

        private void postTestButton_Click(object sender, EventArgs e)
        {
            PostByWebRequest();
        }


        private void PostByWebRequest()
        {
            try
            {
                CookieContainer cookieContainer = new CookieContainer();

                ///////////////////////////////////////////////////
                // 1.打开 MyLogin.aspx 页面，获得 GetVeiwState & EventValidation
                ///////////////////////////////////////////////////                
                // 设置打开页面的参数
                string URI = "http://localhost:1165/WebTest/MyLogin.aspx";
                HttpWebRequest request = WebRequest.Create(URI) as HttpWebRequest;
                request.Method = "GET";
                request.KeepAlive = false;

                // 接收返回的页面
                HttpWebResponse response = request.GetResponse() as HttpWebResponse;
                System.IO.Stream responseStream = response.GetResponseStream();
                System.IO.StreamReader reader = new System.IO.StreamReader(responseStream,Encoding.UTF8);
                string srcString = reader.ReadToEnd();

                // 获取页面的 VeiwState                
                string viewStateFlag = "id=\"__VIEWSTATE\" value=\"";
                int i = srcString.IndexOf(viewStateFlag) + viewStateFlag.Length;
                int j = srcString.IndexOf("\"", i);
                string viewState = srcString.Substring(i, j - i);

                // 获取页面的 EventValidation                
                string eventValidationFlag = "id=\"__EVENTVALIDATION\" value=\"";
                i = srcString.IndexOf(eventValidationFlag) + eventValidationFlag.Length;
                j = srcString.IndexOf("\"", i);
                string eventValidation = srcString.Substring(i, j - i);

                ///////////////////////////////////////////////////
                // 2.自动填充并提交 MyLogin.aspx 页面
                ///////////////////////////////////////////////////
                // 提交按钮的文本
                string submitButton = "登录";

                // 用户名和密码
                string userName = "1";
                string password = "1";

                // 将文本转换成 URL 编码字符串
                viewState = System.Web.HttpUtility.UrlEncode(viewState);
                eventValidation = System.Web.HttpUtility.UrlEncode(eventValidation);
                submitButton = System.Web.HttpUtility.UrlEncode(submitButton);

                // 要提交的字符串数据。格式形如:user=uesr1&password=123
                string formatString = "userName={0}&password={1}&loginButton={2}&__VIEWSTATE={3}&__EVENTVALIDATION={4}";
                string postString = string.Format(formatString, userName, password, submitButton, viewState, eventValidation);

                // 将提交的字符串数据转换成字节数组
                byte[] postData = Encoding.ASCII.GetBytes(postString);

                // 设置提交的相关参数
                request = WebRequest.Create(URI) as HttpWebRequest;
                request.Method = "POST";
                request.KeepAlive = false;
                request.ContentType = "application/x-www-form-urlencoded";
                request.CookieContainer = cookieContainer;
                request.ContentLength = postData.Length;

                // 提交请求数据
                System.IO.Stream outputStream = request.GetRequestStream();
                outputStream.Write(postData, 0, postData.Length);
                outputStream.Close();

                // 接收返回的页面
                response = request.GetResponse() as HttpWebResponse;
                responseStream = response.GetResponseStream();
                reader = new System.IO.StreamReader(responseStream,Encoding.GetEncoding("GB2312"));
                srcString = reader.ReadToEnd();

                ///////////////////////////////////////////////////
                // 3.打开 Default.aspx 页面
                ///////////////////////////////////////////////////
                // 设置打开页面的参数
                URI = "http://localhost:1165/WebTest/Default.aspx";
                request = WebRequest.Create(URI) as HttpWebRequest;
                request.Method = "GET";
                request.KeepAlive = false;
                request.CookieContainer = cookieContainer;

                // 接收返回的页面
                response = request.GetResponse() as HttpWebResponse;
                responseStream = response.GetResponseStream();
                reader = new System.IO.StreamReader(responseStream, Encoding.UTF8);
                srcString = reader.ReadToEnd();

                ///////////////////////////////////////////////////
                // 4.分析返回的页面
                ///////////////////////////////////////////////////
                //  
            }
            catch (WebException we)
            {
                string msg = we.Message;
            }  

        }
    }
}