ASP.NET访问网址并读取响应的内容

想在代码中像AJAX一样访问一个URL，并对结果进行解析，可以使用以下代码实现：

string URL = "要访问的网址+参数";
WebClient client = new WebClient();

Stream data = client.OpenRead(URL);
StreamReader reader = new StreamReader(data);

string str = reader.ReadLine(); 

先using System.Net;
再WebClient w = new WebClient();
w.DownloadString(url)返回的就是网址为url的网页的内容

string str2 = client.DownloadString(URL);
 Label1.Text = str2;