WebClien簡單樣本（一）

MSDN:WebClient提供向 URI 標識的資源發送資料和從 URI 標識的資源接收資料的公用方法.

Demo(一):簡單的請求請求一個頁面內容

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using System;using System.IO;using System.Net;namespace ConsoleApplication2{    class Program    {        static void Main(string[] args)        {            String url = "http://www.baidu.com";                        //先設定代理(在使用代理進行上網的時候用，如果沒有使用代理則無需設定)            WebProxy proxy = new WebProxy("192.168.19.9", 80);                                      //建立 Proxy 伺服器設定對象 的執行個體            proxy.BypassProxyOnLocal = false;                                                       //Proxy 伺服器需要驗證            proxy.Credentials = new NetworkCredential("jiaquanzhen", "abcd_123", "yellowpage");     //使用者名稱密碼            GlobalProxySelection.Select = proxy;            //開始請求            WebClient client = new WebClient();            //佈建要求的資源種類            client.Headers.Add("Accept", @"image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash,                                         application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*");            client.Headers.Add("Accept-Language", "zh-cn,zh;q=0.5");            //擷取網上資源的stream            System.IO.Stream stream = client.OpenRead(url);            //解碼擷取內容            System.IO.StreamReader reader = new System.IO.StreamReader(stream, System.Text.Encoding.UTF8);            String str = reader.ReadToEnd();            Console.WriteLine(str);        }    }}

Demo(二):非同步請求擷取資料

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using System;using System.Web;using System.Web.UI;using System.IO;using System.Net;using System.Text;namespace WebApp{    public partial class _Default : System.Web.UI.Page    {        protected void Page_Load(object sender, EventArgs e)        {            this.btnBegin.Click += new EventHandler(btnBegin_Click);        }        void btnBegin_Click(object sender, EventArgs e)        {            //請求的url            Uri uri = new Uri("http://www.baidu.com");            //初始化webclient，並設定頭屬性            WebClient client = new WebClient();            client.Headers.Add("Accept", @"image/gif,image/x-xbitmap,image/jpeg,application/x-shockwave-flash,                                        appllication/vnd.ms-excel,application/vnd.ms-powerpoint,aplication/msword,*/*");            client.Headers.Add("Accept-Language", "zh-cn,zh;q=0.5");            //進行非同步讀取            client.OpenReadCompleted += new OpenReadCompletedEventHandler(client_OpenReadCompleted);            client.OpenReadAsync(uri);        }        //回呼函數        void client_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)        {            Stream stream = e.Result;            StreamReader reader = new StreamReader(stream, Encoding.Default);            String str = reader.ReadToEnd();            Response.Write(str);        }    }}