silverlight中获取网页代码示例

最新推荐文章于 2021-02-21 05:55:01 发布

最新推荐文章于 2021-02-21 05:55:01 发布 · 105 阅读

本文介绍如何在Silverlight中实现跨域访问，并通过封装类来获取网页内容，包括添加crossdomain.xml策略文件、使用Webclient下载字符串及处理随机数防缓存的方法。

在silverlight中如果要跨域访问，则需要在被访问网站的根目录下添加策略文件crossdomain.xml。内容如下（可以更细致配置，可以查阅相关资料）：

<?xml version="1.0"?>  <cross-domain-policy> <allow-access-from domain="*" /> </cross-domain-policy>

在silverlight中使用webclient来获取网页内容，这里我简单封装了一个类。

需要using System.Net;

public class SuperWebRequest { public SuperWebRequest(string url, Delegate onComplete) { requestURL = url; webClientOnCompet = onComplete; webClient.DownloadStringCompleted += new DownloadStringCompletedEventHandler(webClient_DownloadStringCompleted); Random rand = new Random(); bool add_flag = false; for (int i = 0; i < url.Length; i++) { if (url[i] == '?') { add_flag = true; break; } } Uri endpoint; if (add_flag) endpoint = new Uri(url + "&rand=" + rand.Next()); else endpoint = new Uri(url + "?rand=" + rand.Next());//添加随机数防止缓存 webClient.DownloadStringAsync(endpoint); } private void webClient_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e) { if (!e.Cancelled && e.Error == null) { //回调 Super.objMainPage.Dispatcher.BeginInvoke(webClientOnCompet, e.Result.ToString()); } else { MessageBox.Show("web通信异常" + e.Error.Message.ToString()); } } private WebClient webClient = new WebClient(); private Delegate webClientOnCompet; private string requestURL; }

使用方法：

定义带模板委托

public delegate void DelegateSingleParam<T>(T t);

调用

SuperWebRequest myWebRequest = new SuperWebRequest(
Config.WebRoot+"lastvolumn.xml", new DelegateSingleParam<string>(OnLoadLastVolumn));

回调: data即网页代码

private void OnLoadLastVolumn(string data)
{

}