1.WebClient类
在System.Net空间下，提供向URI标识的目标发送数据和从URI标识的目标接收数据的类。
获取数据通过OpenReadAync，完成时OpenReadCompleted
private void DoWebClient()
{
string url = "http://www.qq.com";
WebClient client = new WebClient();
client.OpenReadAsync(new Uri(url));
client.OpenReadCompleted += new OpenReadCompletedEventHandler(WebClient_OpenReadCompleted);
}
private void WebClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
using (StreamReader reader = new StreamReader(e.Result,DBCSCodePage.DBCSEncoding.GetDBCSEncoding("gb2312")))
{
string contents = reader.ReadToEnd();
int begin = contents.ToString().IndexOf("<title>");
int end = contents.ToString().IndexOf("</title>");
//UI线程调用，直接更新界面
ClientText.Text = contents.ToString().Substring(begin + 7, end - begin - 7);
}
}
2.HttpWebRequest 类
在System.Net空间下，提供WebRequest类的HTTP的实现
private void DoHttpWebRequest()
{
string url = "http://www.baidu.com";
WebRequest request = HttpWebRequest.Create(url);
IAsyncResult result = request.BeginGetResponse(ResponseCallBack, request);
}
private void ResponseCallBack(IAsyncResult result)
{
HttpWebRequest req = result.AsyncState as HttpWebRequest;
WebResponse res = req.EndGetResponse(result);
using(Stream stream=res.GetResponseStream())
using (StreamReader reader = new StreamReader(stream, DBCSCodePage.DBCSEncoding.GetDBCSEncoding("gb2312")))
{
string contents = reader.ReadToEnd();
int begin = contents.ToString().IndexOf("<title>");
int end = contents.ToString().IndexOf("</title>");
//基于后台运行，不在UI线程
Dispatcher.BeginInvoke(() => { ReqText.Text = contents.ToString().Substring(begin + 7, end - begin - 7); });
}
}
ps:DBCSCodePage就是用来解决乱码问题的