c# - Get current WebBrowser DOM as HTML

Question

I want to use the HTML ability pack on a WebBrowser that has loaded all the things I need (It clicks a button with code to load every video on the channel) (It loads a YouTube channel, and then loads all the videos on said channel.) Now if I try to get all the videos details (I have a working code that gets the first 30 videos of a channel into a listview) it will still show only the first 30, but I have all the videos loaded on the WebBrowser page (It shows all videos) I am using this to get whats currently loaded from the WebBrowser

but it still only loads the first 30 videos instead of all the videos loaded from the WebBrowser .

Answer 1

如果目标网站大量使用 AJAX（如 Youtube 那样），则很难（如果不是不可能）确定页面何时完成加载和执行所有动态脚本。但是您可以通过处理window.onload事件并为非确定性 AJAX 调用留出一两秒钟的时间来接近。然后调用webBrowser.Document.DomDocument.documentElement.outerHTMLviadynamic获取当前渲染的 HTML。

例子：

private void Form1_Load(object sender, EventArgs e)
{
    DownloadAsync("http://www.example.com").ContinueWith(
        (task) => MessageBox.Show(task.Result),
        TaskScheduler.FromCurrentSynchronizationContext());
}

async Task<string> DownloadAsync(string url)
{
    TaskCompletionSource<bool> onloadTcs = new TaskCompletionSource<bool>();
    WebBrowserDocumentCompletedEventHandler handler = null;

    handler = delegate
    {
        this.webBrowser.DocumentCompleted -= handler;

        // attach to subscribe to DOM onload event
        this.webBrowser.Document.Window.AttachEventHandler("onload", delegate
        {
            // each navigation has its own TaskCompletionSource
            if (onloadTcs.Task.IsCompleted)
                return; // this should not be happening
            // signal the completion of the page loading
            onloadTcs.SetResult(true);
        });
    };

    // register DocumentCompleted handler
    this.webBrowser.DocumentCompleted += handler;

    // Navigate to url
    this.webBrowser.Navigate(url);

    // continue upon onload
    await onloadTcs.Task;

    // artificial delay for AJAX
    await Task.Delay(1000);

    // the document has been fully loaded, can access DOM here
    return ((dynamic)this.webBrowser.Document.DomDocument).documentElement.outerHTML;
}

[编辑]这是帮助解决 OP 问题的最后一段代码：

HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
doc.LoadHtml(((dynamic)this.webBrowser1.Document.DomDocument).documentElement.ou‌​terHTML);