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 }