在没有做题目中所述的内容的时候，感觉这应该是很简单的东西，但是当真正开始做的时候却发现，有很多问题
现在在这里写出来，供和我一样水平不高的参考一下。
在写本文之前参照了一下文章
欢迎使用CSDN论坛阅读器 : CSDN Reader(附全部源代码) 最新版本：20070212 http://www.cnblogs.com/feiyun0112/archive/2006/09/20/509783.htmlC#通过webRequest保持在同一Session中Post数据 http://blog.csdn.net/crabo/archive/2005/12/08/547092.aspxc# 模拟Asp.net页面中的某个按钮的点击，向web服务器发出请求
主要就组织要提交的数据，然后以post方式提交。
假设我们有如下的网页
Asp.net网页内容
1<%
@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
2
3<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
4
5<html xmlns="http://www.w3.org/1999/xhtml" >
6<head runat="server">
7 <title>无标题页</title>
8</head>
9<body>
10 <form id="form1" runat="server">
11 <div>
12 <table>
13 <tr>
14 <td> 姓名：</td><td><asp:TextBox ID="txtName" runat="server"></asp:TextBox></td>
15 </tr>
16 <tr>
17 <td> 昵称：</td><td><asp:TextBox ID="txtPwd" runat="server" TextMode="Password" Width="149px"></asp:TextBox></td>
18 </tr>
19 </table>
20 <asp:Button ID="btnUpdate" runat="server" Text="Longon" OnClick="btnUpdate_Click" Width="60px" />
21 <asp:Button ID="btnClose" runat="server" OnClick="btnClose_Click" Text="Close" /><br />
22
23 </div>
24 </form>
25</body>
26</html>
用IE访问这个页面的时候可以得到如下的输出
客户端 代码
1
2
3<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
4
5<html xmlns="http://www.w3.org/1999/xhtml" >
6<head><title>
7 无标题页
8</title></head>
9<body>
10 <form name="form1" method="post" action="Default.aspx" id="form1">
11<div>
12<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMTg4ODA4NDE0NmRk6Ma0MaCJKrrNLGLfO4qYNezoxY4=" />
13</div>
14
15 <div>
16 <table>
17 <tr>
18 <td> 姓名：</td><td><input name="txtName" type="text" id="txtName" /></td>
19 </tr>
20 <tr>
21 <td> 昵称：</td><td><input name="txtPwd" type="password" id="txtPwd" style="149px;" /></td>
22 </tr>
23 </table>
24 <input type="submit" name="btnUpdate" value="Logon" id="btnUpdate" style="60px;" />
25 <input type="submit" name="btnClose" value="Close" id="btnClose" /><br />
26
27 </div>
28
29<div>
30
31 <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEWBQKcopufDgLEhISFCwKd+7qdDgLynailDAKT+PmaCJleqITXMfQuE9LK49YoxHV2oTzQ" />
32</div></form>
33</body>
34</html>
35
由上面的代码可以看出除了txtName，txtPwd以及两个按钮外，多出了两个__VIEWSTATE，__EVENTVALIDATION这四个表单需要提交到的，要模拟哪个按钮，在加上哪个按钮的表单的值就可以了，如：
btnUpdate=Logon
在拼接提交的字符串的时候注意一下，用System.Web.HttpUtility.UrlEncode方法转换成Url编码的字符串。
下面是针对这个页面的btnUpdate按钮的提交数据
1 string __VIEWSTATE = "/wEPDwUKMTg4ODA4NDE0NmRk6Ma0MaCJKrrNLGLfO4qYNezoxY4=";
2 string __EVENTVALIDATION = "/wEWBQKcopufDgLEhISFCwKd+7qdDgLynailDAKT+PmaCJleqITXMfQuE9LK49YoxHV2oTzQ";
3
4 __VIEWSTATE = System.Web.HttpUtility.UrlEncode(__VIEWSTATE);
5
6 __EVENTVALIDATION = System.Web.HttpUtility.UrlEncode(__EVENTVALIDATION);
7
8 string strPostData = String.Format("__VIEWSTATE={0}&txtName={1}&txtPwd={2}&btnUpdate=Longon&__EVENTVALIDATION={3}"
9 , __VIEWSTATE, this.txtName.Text, this.txtPassword.Text, __EVENTVALIDATION
10 );
然后创建一个HttpWebRequest对象，设置提交方式是post，然后把上面准备的字符串写进请求数据流里
基本上就可以了
如果有需要在访问不同页面时保存Session的话，需要设置HttpWebRequest对象的CookieContainer属性，保证每次设置的CookieContainer都是同一个对象就可以了。
下面是这个类就是向WEB页面发出请求，并得到返回数据的类
读取网页内容
1using System;
2using System.Net;
3
4namespace Dlse.Com.Cn.Why
5{
6
class WebPageReader
7
{
8
9 /**//// <summary>
10 /// cookie
11
/// </summary>
12 private CookieCollection _Cookies = new CookieCollection();
13
14 /**//// <summary>
15 /// 保持提交到同一个Session
16 /// </summary>
17 private CookieContainer cookieContainer = new CookieContainer();
18
19 /**//// <summary>
20 /// 保持连接
21 /// </summary>
22 private bool isKeepAlive = false;
23
24 public bool IsKeepAlive
25 {
26 get { return isKeepAlive; }
27 set { isKeepAlive = value; }
28 }
29
30
31
32 public string GetHTML(string URL)
33 {
34 return GetHTML(URL, "", System.Text.Encoding.ASCII);
35 }
36
37 public string GetHTML(string URL, string PostData)
38 {
39 return GetHTML(URL, PostData, System.Text.Encoding.ASCII);
40 }
41
42 public string GetHTML(string URL, System.Text.Encoding encoding)
43 {
44 return GetHTML(URL,"",encoding );
45 }
46
47 /**//// <summary>
48 /// 获取指定地址的html
49 /// </summary>
50 /// <param name="URL"></param>
51 /// <param name="PostData"></param>
52 /// <param name="encoding"></param>
53 /// <returns></returns>
54 public string GetHTML(string URL, string PostData, System.Text.Encoding encoding)
55 {
56 isKeepAlive = false;
57 string _Html = "";
58
59 HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(URL);
60 request.Accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/msword, application/x-shockwave-flash, */*";
61
62
63 if (_Cookies.Count > 0)
64 {
65 request.CookieContainer.Add(new Uri(URL), _Cookies);
66 }
67 else
68 {
69 request.CookieContainer = this.cookieContainer;
70 }
71
72 //提交的数据
73 if (PostData != null && PostData.Length > 0)
74 {
75 request.ContentType = "application/x-www-form-urlencoded";
76 request.Method = "POST";
77
78 byte[] b = encoding.GetBytes(PostData);
79 request.ContentLength = b.Length;
80 using (System.IO.Stream sw = request.GetRequestStream())
81 {
82 try
83 {
84 sw.Write(b, 0, b.Length);
85 }
86 catch (Exception ex)
87 {
88 throw new Exception("Post Data Error!!", ex);
89 }
90 finally
91 {
92 if (sw != null) { sw.Close(); }
93 }
94 }
95 }
96
97
98 HttpWebResponse response = null;
99 System.IO.StreamReader sr = null;
100
101 try
102 {
103
104 response = (HttpWebResponse)request.GetResponse();
105
106 _Cookies = response.Cookies;
107
108 sr = new System.IO.StreamReader(response.GetResponseStream(), encoding);
109
110 _Html = sr.ReadToEnd();
111
112 }
113 catch (WebException webex)
114 {
115 if (webex.Status == WebExceptionStatus.KeepAliveFailure)
116 {
117 isKeepAlive = true;
118 }
119 else
120 {
121 throw new Exception("DownLoad Data Error", webex);
122 }
123 }
124 catch (System.Exception ex)
125 {
126 throw new Exception("DownLoad Data Error", ex);
127 }
128 finally
129 {
130 if (sr != null) { sr.Close(); }
131 if (response != null) { response.Close(); }
132 response = null;
133 request = null;
134 }
135
136 return _Html;
137
138 }
139 }
140
}
141
使用方法如下
WebPageReader的使用方法
1private WebPageReader webReader = new WebPageReader();
2
3string __VIEWSTATE = "/wEPDwUKMTg4ODA4NDE0NmRk6Ma0MaCJKrrNLGLfO4qYNezoxY4=";
4string __EVENTVALIDATION = "/wEWBQKcopufDgLEhISFCwKd+7qdDgLynailDAKT+PmaCJleqITXMfQuE9LK49YoxHV2oTzQ";
5
6__VIEWSTATE = System.Web.HttpUtility.UrlEncode(__VIEWSTATE);
7
8__EVENTVALIDATION = System.Web.HttpUtility.UrlEncode(__EVENTVALIDATION);
9
10string strPostData = String.Format("__VIEWSTATE={0}&txtName={1}&txtPwd={2}&btnUpdate=Longon&__EVENTVALIDATION={3}"
11 , __VIEWSTATE, this.txtName.Text, this.txtPassword.Text, __EVENTVALIDATION
12 );
13string strHTML;
14
15try
16{
17 do
18 {
19 strHTML = webReader.GetHTML("http://localhost:3517/WebSite1/Default.aspx", strPostData);
20 } while (webReader.IsKeepAlive);
21
22
23 this.richTextBox1.Text = strHTML;
24}
25catch (Exception ex)
26{
27 if (ex.InnerException != null)
28 {
29 MessageBox.Show(ex.Message + "\n" + ex.InnerException.Message);
30 }
31 else
32 {
33 MessageBox.Show(ex.Message);
34 }
35}