c# 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
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
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 ="width:149px;" /></ td >
22 </ tr >
23 </ table >
24 < input type ="submit" name ="btnUpdate" value ="Logon" id ="btnUpdate" style ="width: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
1 using System;
2 using System.Net;
3
4 namespace 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
1 private WebPageReader webReader = new WebPageReader();
2
3 string __VIEWSTATE = " /wEPDwUKMTg4ODA4NDE0NmRk6Ma0MaCJKrrNLGLfO4qYNezoxY4= " ;
4 string __EVENTVALIDATION = "/wEWBQKcopufDgLEhISFCwKd+7qdDgLynailDAKT+PmaCJleqITXMfQuE9LK49YoxHV2oTzQ " ;
5
6 __VIEWSTATE = System.Web.HttpUtility.UrlEncode(__VIEWSTATE);
7
8 __EVENTVALIDATION = System.Web.HttpUtility.UrlEncode(__EVENTVALIDATION);
9
10 string strPostData = String.Format( " __VIEWSTATE={0}&txtName={1}&txtPwd={2}&btnUpdate=Longon&__EVENTVALIDATION={3} "
11 , __VIEWSTATE, this .txtName.Text, this .txtPassword.Text, __EVENTVALIDATION
12 );
13 string strHTML;
14
15 try
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 }
25 catch (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 }