Question

我用C＃应用程序开发了一个简单的ID检查Windows窗体，可以通过使用webbrowser控件传递到网页并获得答复来检查一组给定的ID是否有效，并且一切正常，这需要40到60秒的时间20 Ids.ones by one.Now。我现在想使用C＃中的高级线程概念来加速相同的过程。

代码运行良好，我想使用线程来提高性能。任何简单的建议对今天都是有帮助的

private void button2_Click(object sender, EventArgs e)
       {
           string url = "https://idscheckingsite.com";
           WebBrowser wb = new WebBrowser();
           wb.ScriptErrorsSuppressed = true;
           wb.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(Final_DocumentCompleted);
           wb.Navigate(url);

       }

private void Final_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
       {
           WebBrowser wbs = sender as WebBrowser;
           wbs.Document.GetElementById("pannumber").InnerText = ListsofIds[ids];
           wbs.Document.GetElementById("frmType1").SetAttribute("value", "24Q");
           HtmlElement btnlink = wbs.Document.GetElementById("clickGo1");
           btnlink.InvokeMember("Click");

           //string response = wbs.DocumentText;
           wbs.DocumentCompleted -= new WebBrowserDocumentCompletedEventHandler(Final_DocumentCompleted);
           wbs.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(Final_result);
       }


private void Final_result(object sender, WebBrowserDocumentCompletedEventArgs e)
       {

           WebBrowser wbResult = sender as WebBrowser;

           string status = wbResult.Document.GetElementById("status").InnerText;
           string name = wbResult.Document.GetElementById("name").InnerText;

           wbResult.DocumentCompleted -= new WebBrowserDocumentCompletedEventHandler(Final_result);
           wbResult.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(Final_DocumentCompleted);

           DataRow dr = dt.NewRow();

           dr[0] = PANNumber[ids];
           dr[1] = status;
           dr[2] = name;

           dt.Rows.Add(dr);
           ++ids;

           if (ids < 20)
               wbResult.Navigate(vurl);
           else
           {
               dataGridView1.DataSource = dt;
           }
       }

工作正常，但需要使用高级C＃线程概念（如果有）来最大程度地提高性能。

Answer 1

这是我的建议。单击button2时，将启动许多工作程序任务。合理的数字是4，但是您可以尝试使用不同的数字，直到获得最佳性能。每个辅助任务将使用其自己的WebBrowser控件，并将调用ID的子集。例如，工作程序任务0将调用ID 4、8、12、16和20，工作程序任务1将调用1、5、9、13和17等。然后将等待所有工作程序任务完成，然后可以更新DataGridView。不涉及多线程。一切都发生在UI线程中。不需要锁定或其他线程同步。

private async void button2_Click(object sender, EventArgs e)
{
    string url = "https://idscheckingsite.com";
    const int WORKER_TASKS_COUNT = 4;
    var workerTasks = new Task[WORKER_TASKS_COUNT];
    for (int i = 0; i < WORKER_TASKS_COUNT; i++)
    {
        workerTasks[i] = DoWorkAsync(i);
    }
    await Task.WhenAll(workerTasks);
    dataGridView1.DataSource = dt;

    async Task DoWorkAsync(int workerIndex)
    {
        using (var wb = new WebBrowser())
        {
            wb.ScriptErrorsSuppressed = true;
            for (int i = 0; i < ListsofIds.Length; i++)
            {
                if (i % WORKER_TASKS_COUNT != workerIndex) continue;
                wb.Navigate(url);
                await wb; // await for the next DocumentCompleted
                wb.Document.GetElementById("pannumber").InnerText = ListsofIds[i];
                wb.Document.GetElementById("frmType1").SetAttribute("value", "24Q");
                HtmlElement btnlink = wb.Document.GetElementById("clickGo1");
                btnlink.InvokeMember("Click");
                await wb; // await for the next DocumentCompleted
                string status = wb.Document.GetElementById("status").InnerText;
                string name = wb.Document.GetElementById("name").InnerText;
                DataRow dr = dt.NewRow();
                dr[0] = PANNumber[i];
                dr[1] = status;
                dr[2] = name;
                dt.Rows.Add(dr);
            }
        }
    }
}

上面的代码使用了一种有趣的技术来简化WebBrowser控件的导航。它不是通过手动订阅和取消订阅DocumentCompleted事件，而是通过await设置WebBrowser控件来自动进行此操作。通常这是不可能的，但是我们可以通过创建返回TaskAwaiter的扩展方法来实现：

public static class WebBrowserExtensions
{
    public static TaskAwaiter<Uri> GetAwaiter(this WebBrowser wb)
    {
        var tcs = new TaskCompletionSource<Uri>();
        WebBrowserDocumentCompletedEventHandler handler = null;
        handler = (_, e) =>
        {
            wb.DocumentCompleted -= handler;
            tcs.TrySetResult(e.Url);
        };
        wb.DocumentCompleted += handler;
        return tcs.Task.GetAwaiter();
    }
}

更新：我自己使用代码后，发现await wb有点令人困惑，因为WebBrowser控件中有许多事件可以等待。因此，我使事件的异步版本（而不是等待者）更加明确和可扩展：

public static class WebBrowserExtensions
{
    public static Task<Uri> DocumentCompletedAsync(this WebBrowser wb)
    {
        var tcs = new TaskCompletionSource<Uri>();
        WebBrowserDocumentCompletedEventHandler handler = null;
        handler = (_, e) =>
        {
            wb.DocumentCompleted -= handler;
            tcs.TrySetResult(e.Url);
        };
        wb.DocumentCompleted += handler;
        return tcs.Task;
    }
}

可以这样使用：

await wb.DocumentCompletedAsync();

然后创建诸如NavigatedAsync或DocumentTitleChangedAsync之类的更多扩展方法变得很简单。

更新：无休止的等待不是很好，因此可以将超时（以毫秒表示）添加为已等待的扩展方法中的参数。由于整个代码旨在专门在UI线程中运行，因此我使用了System.Windows.Forms.Timer，尽管通常CancellationToken会更方便。该代码涉及一些以避免内存泄漏的问题，这对于打算运行多个小时并执行数千个Web请求的应用程序来说可能是个问题。

public static class WebBrowserExtensions
{
    public static Task<Uri> DocumentCompletedAsync(this WebBrowser wb, int timeout)
    {
        var tcs = new TaskCompletionSource<Uri>();
        WebBrowserDocumentCompletedEventHandler handler = null;
        var timeoutRegistration = WithTimeout(tcs, timeout,
            () => wb.DocumentCompleted -= handler);
        handler = (_, e) =>
        {
            wb.DocumentCompleted -= handler;
            timeoutRegistration.Unregister();
            tcs.TrySetResult(e.Url);
        };
        wb.DocumentCompleted += handler;
        return tcs.Task;
    }
    public static Task<Uri> DocumentCompletedAsync(this WebBrowser wb)
    {
        return wb.DocumentCompletedAsync(30000); // Default timeout 30 sec
    }

    private static TimeoutRegistration WithTimeout<T>(
        TaskCompletionSource<T> tcs, int timeout, Action eventRemove)
    {
        if (timeout == Timeout.Infinite) return default;
        var timer = new System.Windows.Forms.Timer();
        timer.Tick += (s, e) =>
        {
            timer.Enabled = false;
            timer = null;
            eventRemove();
            eventRemove = null;
            tcs.SetException(new TimeoutException());
            tcs = null;
        };
        timer.Interval = timeout;
        timer.Enabled = true;
        return new TimeoutRegistration(() =>
        {
            if (timer == null) return;
            timer.Enabled = false;
            // Make everything null to avoid memory leaks
            timer = null;
            eventRemove = null;
            tcs = null;
        });
    }

    private struct TimeoutRegistration
    {
        private Action _unregister;
        public TimeoutRegistration(Action unregister)
        {
            _unregister = unregister;
        }
        public void Unregister()
        {
            if (_unregister == null) return;
            _unregister();
            _unregister = null;
        }
    }

}

线程概念可改善C＃中的Web浏览器URL导航过程

1 个答案: