c#获取网页中指定的字符串信息的实例代码

      privatevoidbutton2_Click(objectsender,EventArgse)
         {
             //CreatearequestfortheURL.  
             WebRequestrequest=WebRequest.Create("http://www.baidu.com/");
             //Ifrequiredbytheserver,setthecredentials.
             request.Credentials=CredentialCache.DefaultCredentials;
             //Gettheresponse.
         HttpWebResponseresponse=(HttpWebResponse)request.GetResponse();
             //Displaythestatus.
            MessageBox.Show(response.StatusDescription);
            Console.WriteLine(response.StatusDescription);
            //Getthestreamcontainingcontentreturnedbytheserver.
            StreamdataStream=response.GetResponseStream();
            //OpenthestreamusingaStreamReaderforeasyaccess.
            StreamReaderreader=newStreamReader(dataStream,Encoding.Default);
            //Readthecontent.
            stringresponseFromServer=reader.ReadToEnd();
            //截取数据
            inti=responseFromServer.IndexOf("京");
            stringdataBid=responseFromServer.Substring(i,12);

            //Displaythecontent.
            MessageBox.Show(dataBid);
            Console.WriteLine(responseFromServer);
            //Cleanupthestreamsandtheresponse.
            reader.Close();
            dataStream.Close();
            response.Close();
        }