利用WebRequest来实现模拟浏览器通过Post方式向服务器提交数据

//通过Post发送的数据
string payload="chkbook=book&keyword=管理";
WebRequest req = WebRequest.Create("http://localhost/pceo/Search.aspx");
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
StringBuilder UrlEncoded = new StringBuilder();
Char[] reserved = {'?', '=', '&'};
byte[] SomeBytes = null;
if (payload != null)
{
int i=0, j;
while(i<payload.Length)
{
j=payload.IndexOfAny(reserved, i);
if (j==-1)
{
UrlEncoded.Append(HttpUtility.UrlEncode(payload.Substring(i, payload.Length-i),System.Text .Encoding .GetEncoding ("gb2312")));
break;
}
UrlEncoded.Append(HttpUtility.UrlEncode(payload.Substring(i, j-i),System.Text .Encoding .GetEncoding ("gb2312")));
UrlEncoded.Append(payload.Substring(j,1));
i = j+1;
}
SomeBytes = Encoding.Default.GetBytes(UrlEncoded.ToString());
req.ContentLength = SomeBytes.Length;
Stream newStream = req.GetRequestStream();
newStream.Write(SomeBytes, 0, SomeBytes.Length);
newStream.Close();
}
else
{
req.ContentLength = 0;
}
try
{
WebResponse result = req.GetResponse();
Stream ReceiveStream = result.GetResponseStream();

Byte[] read = new Byte[512];
int bytes = ReceiveStream.Read(read, 0, 512);

txtHTML.InnerHtml = "";
while (bytes > 0)
{

// 注意：
// 下面假定响应使用 UTF-8 作为编码方式。
// 如果内容以 ANSI 代码页形式（例如，932）发送，则使用类似下面的语句：
// Encoding encode = System.Text.Encoding.GetEncoding("shift-jis");
Encoding encode = System.Text.Encoding.GetEncoding("gb2312");
txtHTML.InnerHtml = txtHTML.InnerHtml + encode.GetString(read, 0, bytes);
bytes = ReceiveStream.Read(read, 0, 512);
}
}
catch(Exception)
{
txtHTML.InnerHtml = "检索页时出错";
}