C#网络编程基础

1.      DNS使用

DNS类是一个静态类，提供从网络上获取特定主机的信息。

//通过主机名获取域名

IPHostEntry host = Dns.GetHostEntry(textBox1.Text);

Label1.Text = host.HostName;

//通过主机名获取IP

IPHostEntry host = Dns.GetHostEntry(textBox1.Text);

Label2.Text = host.AddressList[1].ToString();

   

2.      WebClient使用

WebClient提供从指定的URL上获取资源或向其发送数据。

  

(1)  WebClient从网络上获取数据

WebClient client = new WebClient();

//textBox1.Text一个URL

Streamstream = client.OpenRead(textBox1.Text);

intbyteCount = 0;

do

  {

                byteCount=stream.ReadByte();

                if(byteCount>0)

                    richTextBox1.Text+=Convert.ToChar(byteCount);

} while(byteCount>0);

stream.Close();

(2)        下载文件

            WebClient client = new WebClient();

            FolderBrowserDialogdlg = new FolderBrowserDialog();

            if(dlg.ShowDialog()==DialogResult.OK)

            {

                stringpath = dlg.SelectedPath+"\\" +

             //文件存放的位置

             Path.GetFileName(textBox2.Text);

             client.DownloadFile(textBox2.Text,path);

          }

3.      WebRequest和WebResponse

         分别为向指定的URL发送请求和接受应答的类。

          WebRequest request = WebRequest.Create(textBox1.Text);

            WebResponseresponse = request.GetResponse();

            Streamstream = response.GetResponseStream();

           //编码方式任意

            Encodingencode = Encoding.GetEncoding("utf-8");

            StreamReaderreader = new StreamReader(stream,encode);

            Char[]buffer = new Char[100];

            intcount = reader.Read(buffer, 0, 100);

            while(count > 0)

            {

                stringstr = new string(buffer,0, 100);

                richTextBox1.Text += str;

                count = reader.Read(buffer, 0, 100);

       }