从Silverlight调用外部网站

问题描述

我正在编写一个小型的Silverlight应用程序，只是为了尝试Silverlight.我的想法是制作一个小型应用程序，以检查网站是否在线.用户输入网址即可正常运行，我的应用程序每5分钟检查一次正常运行时间.

I am writing a small silverlight app just to try silverlight. My idea is to make a small app that checks if websites are online. It works by the user inputting a URL and my app checks it uptime every 5 minutes.

但是，每当我执行webrequest时，都会收到以下安全异常.阅读 http://msdn.microsoft. com/en-us/library/system.net.httpwebrequest(VS.95).aspx 似乎表明silverlight不允许跨域连接.因此，没有办法使我的想法在Silverlight中发挥作用吗?

But when ever I do a webrequest I get the security exception below. Reading http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest(VS.95).aspx it seems to indicate that silverlight doesn't allow crossdomain connection. So is there no way to make my idea work in silverlight?

示例代码:

     WebRequest testHTTP = null;
            try
            {
                testHTTP = WebRequest.Create(serverToCheck);
            }
            catch (UriFormatException ufe)
            {
                try
                {
                    testHTTP = WebRequest.Create("http://" + serverToCheck);
                }
                catch (UriFormatException ufe1)
                {
                    MessageBox.Show("Invalid server address");

                }
            }
            if (testHTTP != null)
            {
                testHTTP.BeginGetResponse(new AsyncCallback(doCheck), testHTTP);

                }

  void doCheck(IAsyncResult a)
    {
        try
        {
            HttpWebRequest req = (HttpWebRequest)a.AsyncState;
            HttpWebResponse res = (HttpWebResponse)req.EndGetResponse(a);

             Dispatcher.BeginInvoke(() => HTTPStatus.Content = "OK");

        }
        catch (Exception ex)
        {
  //handle exception
        }

    }

例外:{System.Security.SecurityException ---> System.Security.SecurityException:安全错误. 在System.Net.Browser.BrowserHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult) 在System.Net.Browser.BrowserHttpWebRequest处.<> c__DisplayClass5.b__4(对象sendState) 在System.Net.Browser.AsyncHelper中.<> c__DisplayClass2.b__0(对象sendState) ---内部异常堆栈跟踪的结尾--- 在System.Net.Browser.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod，对象状态) 在System.Net.Browser.BrowserHttpWebRequest.EndGetResponse(IAsyncResult asyncResult) 在monitor.Home.doCheck(IAsyncResult a)}

Exception:{System.Security.SecurityException ---> System.Security.SecurityException: Security error. at System.Net.Browser.BrowserHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult) at System.Net.Browser.BrowserHttpWebRequest.<>c__DisplayClass5.b__4(Object sendState) at System.Net.Browser.AsyncHelper.<>c__DisplayClass2.b__0(Object sendState) --- End of inner exception stack trace --- at System.Net.Browser.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state) at System.Net.Browser.BrowserHttpWebRequest.EndGetResponse(IAsyncResult asyncResult) at monitor.Home.doCheck(IAsyncResult a)}

推荐答案

您无法在Silverlight 3中覆盖服务器的跨域策略.在 Silverlight 4 您可以将浏览器"应用程序.

You can't override the cross domain policy of the server in Silverlight 3. In Silverlight 4 you can with a trusted "out of browser" application.

您最好的选择是创建一个与托管Silverlight应用程序的域在同一域上运行的服务，并对其进行检查.

Your best bet is to create a service that runs on the same domain as the one hosting the Silverlight application and have it do the checks.

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