vs2008 测试silverlight做的控件发生安全性异常

vs2008 测试silverlight做的控件发生安全性错误
代码如下 void SearchBtn_Click(object sender, RoutedEventArgs e)
  {
  // Retrieve Topic to Search for from WaterMarkTextBox
  string topic = txtSearchTopic.Text;

  // Construct Digg REST URL
  string diggUrl = String.Format("http://services.digg.com/stories/topic/{0}?count=20&appkey=http%3A%2F%2Fscottgu.com&type=xml", topic);

  // Initiate Async Network call to Digg
  WebClient diggService = new WebClient();
  diggService.DownloadStringCompleted += new DownloadStringCompletedEventHandler(DiggService_DownloadStoriesCompleted);
  diggService.DownloadStringAsync(new Uri(diggUrl));
  }

  void DiggService_DownloadStoriesCompleted(object sender, DownloadStringCompletedEventArgs e)
  {
  if (e.Error == null)
  {
  DisplayStories(e.Result);
  }
  }
 求解

[解决办法]
有没有使用Vs2010调试过呢？效果如何？
[解决办法]
string diggUrl = String.Format("http://services.digg.com/stories/topic/{0}?count=20&appkey=http%3A%2F%2Fscottgu.com&type=xml", topic);

你测试了这个URL了么？其中使用的appkey是http%3A%2F%2Fscottgu.com，你并非这个appkey的拥有者，会出现安全性错误。

服务访问，需要注意服务权限认证后，才能调用成功。