0

第一次在这里发帖，很抱歉从提问开始。

在我的 Windows Phone 7 应用程序中，我有一个由后台代理触发的正在工作的 livetile。但是如何修改代码使 httpwebrequest 在 10 秒后超时？

提前致谢。

protected override void OnInvoke(ScheduledTask task)
    {
        //TODO: Add code to perform your task in background

        var request = (HttpWebRequest)WebRequest.Create(
        new Uri("site.com"));

        request.BeginGetResponse(r =>
        {
            var httpRequest = (HttpWebRequest)r.AsyncState;
            var httpResponse = (HttpWebResponse)httpRequest.EndGetResponse(r);
            using (var reader = new StreamReader(httpResponse.GetResponseStream()))
            {
                var response = reader.ReadToEnd();

                Deployment.Current.Dispatcher.BeginInvoke(new Action(() =>
                {
                    string strResult = response;


                    /// If application uses both PeriodicTask and ResourceIntensiveTask
                    if (task is PeriodicTask)
                    {
                        // Execute periodic task actions here.
                        ShellTile TileToFind = ShellTile.ActiveTiles.FirstOrDefault(x => x.NavigationUri.ToString().Contains("TileID=2"));
                        if (TileToFind != null)
                        {

                            StandardTileData NewTileData = new StandardTileData
                            {
                                BackgroundImage = new Uri("Pin-to-start.png", UriKind.Relative),
                                Title = strResult,
                                Count = null
                            };
                            TileToFind.Update(NewTileData);
                        }
                    }
                    else
                    {
                        // Execute resource-intensive task actions here.
                    }

                    NotifyComplete();
                }));
            }
        }, request);
    }
4

2 回答 2

3

这是我在我的一个应用程序中使用的代码的复制/粘贴。它将在 60 秒后中止连接。

    private static void DoWebRequest(string uri)
    {
        string id = "my_request";

        Timer t = null;
        int timeout = 60; // in seconds

        try
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
            request.Accept = "*/*";
            request.AllowAutoRedirect = true;

            // disable caching.
            request.Headers["Cache-Control"] = "no-cache";
            request.Headers["Pragma"] = "no-cache";

            t = new Timer(
                state =>
                {
                    if (string.Compare(state.ToString(), id, StringComparison.InvariantCultureIgnoreCase) == 0)
                    {
                        logger.Write("Timeout reached for connection [{0}], aborting download.", id);

                        request.Abort();
                        t.Dispose();
                    }
                },
                id,
                timeout * 1000,
                0);

            request.BeginGetResponse(
                r =>
                {
                    try
                    {
                        if (t != null)
                        {
                            t.Dispose();
                        }

                        // your code for processing the results

                    }
                    catch
                    {
                        // error handling.
                    }
                },
                request);
        }
        catch
        {
        }
    }
于 2011-11-02T18:58:09.240 回答
2

但是如何修改代码使 httpwebrequest 在 10 秒后超时？

你的意思是不管超时它都会调用NotifyComplete() 吗？-) 问题是 15 秒后任务终止，并被禁用，直到用户重新启动它（在你的应用程序内）。

我建议将TPL 用于 Silverlight，并利用使用任务设置超时的能力。

就像是：

protected override void OnInvoke(ScheduledTask task)
{
    var fetchTask = FetchData(TimeSpan.FromSeconds(10));
    fetchTask.ContinueWith(x =>
    {
        Deployment.Current.Dispatcher.BeginInvoke(new Action(() =>
        {
            string strResult = x.Result; // mind you, x.Result will be "null" when a timeout occours.

            ...

            NotifyComplete();
        }));
    });
}

private Task<string> FetchData(TimeSpan timeout)
{ 
    var tcs = new TaskCompletionSource<string>();
    var request = (HttpWebRequest)WebRequest.Create(new Uri("site.com"));

    Timer timer = null;
    timer = new Timer(sender =>
    {
        tcs.TrySetResult(null);
        timer.Dispose();
    }, null, (int)timeout.TotalMilliseconds, Timeout.Infinite);

    request.BeginGetResponse(r =>
    {
        var httpRequest = (HttpWebRequest)r.AsyncState;
        var httpResponse = (HttpWebResponse)httpRequest.EndGetResponse(r);
        using (var reader = new StreamReader(httpResponse.GetResponseStream()))
        {
            var response = reader.ReadToEnd();
            tcs.TrySetResult(response);
        }
    });

    return tcs.Task;
}
于 2011-11-03T09:59:28.373 回答