asp.net 需要登陆的网站上下载网页源代码和文件

这个是文件下载类：

using system;
using system.io;
using system.net;
using system.web;

public class srwebclient
{
cookiecontainer cookie;
public srwebclient()
{
cookie = new cookiecontainer();
}

/// <tgdata>
/// <alias>下载web源代码</alias>
/// </tgdata>
public string downloadhtml(string url)
{
httpwebrequest request = httpwebrequest.create(url) as httpwebrequest;
request.cookiecontainer = cookie;
request.allowautoredirect = false;

webresponse res = request.getresponse();
string r = "";

streamreader s1 = new streamreader(res.getresponsestream(), system.text.encoding.default);
try
{
r = s1.readtoend();
}
catch (exception er)
{
log l = new log();
l.writelog("下载web错误", er.tostring());
}
finally
{
res.close();
s1.close();
}

return r;
}

/// <tgdata>
/// <alias>下载文件</alias>
/// </tgdata>
public long downloadfile(string fileurl, string filesavepath)
{
long filelength = 0;
httpwebrequest req = httpwebrequest.create(fileurl) as httpwebrequest;

req.cookiecontainer = cookie;
req.allowautoredirect = true;

httpwebresponse res = req.getresponse() as httpwebresponse;
system.io.stream stream = res.getresponsestream();
try
{
filelength = res.contentlength;

byte[] b = new byte[512];

int nreadsize = 0;
nreadsize = stream.read(b, 0, 512);

system.io.filestream fs = system.io.file.create(filesavepath);
try
{
while (nreadsize > 0)
{
fs.write(b, 0, nreadsize);
nreadsize = stream.read(b, 0, 512);
}
}
finally
{
fs.close();
}
}
catch (exception er)
{
log l = new log();
l.writelog("下载文件错误", er.tostring());
}
finally
{
res.close();
stream.close();
}

return filelength;
}

/// <tgdata>
/// <alias>提交数据</alias>
/// </tgdata>
public void request(string requestpageurl, requestdata data)
{
string strurl = requestpageurl;
httpwebrequest request = httpwebrequest.create(strurl) as httpwebrequest;
httpwebresponse response;

string postdata = data.getdata();
request.referer = requestpageurl;
request.allowautoredirect = false;
request.useragent = "mozilla/4.0 (compatible; msie 6.01; windows nt 5.0)";
request.cookiecontainer = cookie;

uri u = new uri(strurl);

if (postdata.length > 0) //包含要提交的数据　就使用post方式
{
//作为表单请求
request.contenttype = "application/x-www-form-urlencoded";
//方式就是post
request.method = "post";

//把提交的数据换成字节数组
byte[] b = system.text.encoding.default.getbytes(postdata);
request.contentlength = b.length;

stream sw = request.getrequeststream(); //开始提交数据
sw.write(b, 0, b.length);
sw.close();
}

response = request.getresponse() as httpwebresponse;
response.close();
}
}

这个是提交的数据类：

using system.collections;
using system.io;

public class requestdata
{
arraylist arr = new arraylist();
public requestdata()
{

}

public string getdata()
{
string r = "";

for (int i = 0; i < arr.count; i++)
{
data d = (data) arr[i];
if (r.length > 0)
r += "&";
r += d.field + "=" + d.value;
}
return r;
}

public void addfield(string field, string value)
{
data a = new data();
a.field = field;
a.value = value;

arr.add(a);
}

struct data
{
public string field, value;
}
}

代码贴完了，下面是测试代码，因为有些数据涉及到客户的资料，故隐去

using nunit.framework;

[testfixture]
public class testweb
{
[test]
public void testdownseorder()
{
requestdata data = new requestdata();
data.addfield("name", "abc");
data.addfield("password", "121");

srwebclient web = new srwebclient();
web.request("http://127.0.0.1/login.asp", data);

string s = web.downloadhtml("http://127.0.0.1/dingdan.asp");
system.console.writeline(s);
}

[test]
public void testdownfile()
{
requestdata data = new requestdata();
data.addfield("name", "aaa");
data.addfield("password", "bbb");

srwebclient web = new srwebclient();
web.request("http://127.0.0.1/login.asp", data);

web.downloadfile("http://127.0.0.1/download.asp?fileid=1", @"c:\a.txt");
}
}