表单上的 InvokeMember("submit") 不会重定向浏览器

Question

我正在使用 WebBrowser 控件来测试表单提交，在这种特殊情况下，该操作是重定向到另一个结果页面的 MVC 操作。

代码真的很简单……

 void _browser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
 {
     var parentForm = _my_find_form_function();

     parentForm.SetAttribute("action", "http://localhost/tests/TestSubmission");
     parentForm.InvokeMember("submit");
 }

提交后（按预期工作），我原以为会在加载重定向页面后触发下一个 documentcompleted 事件。而是加载相同的页面（带有表单）。

我有什么遗漏吗？

谢谢

Answer 1

好的，抱歉耽搁了，我开始做别的事了……

无论如何，它真的很粗糙，但你应该能够挑选你需要的部分。

最初的想法是从Noseratio找到here。

raisedynamicevent 方法的工作方式与异步导航类似，通过在事件发生后监控文档的状态。当再次确定时，返回。应该处理ajax的东西。需要重新考虑一下，可能会出现很多问题，但希望能对某人有所帮助。

/// the _profileQueue was a queue of URLs i wanted to nav through and find an 
/// form elem and "click" the submit button on
private async void Next()
    {
        Submission res = null;
        if (_profileQueue.TryDequeue(out res))
        {
            // dirty, but hold the details of the url i'm navigating to in the Tag
            _browser.Tag = res;

            var cts = new CancellationTokenSource(Properties.Settings.Default.BrowserNavigationTimeout); // cancel in 10s
            var html = await LoadDynamicPage(res.SiteProfile.URL, cts.Token);

            // this parses the dom once loaded (awaits for the page)
            ProcessSiteProfile();
            Next();
        }
    }

    // navigate and download 
    async Task<string> LoadDynamicPage(string url, CancellationToken token)
    {
        // navigate and await DocumentCompleted
        var tcs = new TaskCompletionSource<bool>();
        WebBrowserDocumentCompletedEventHandler handler = (s, arg) =>
            tcs.TrySetResult(true);

        // i'm keeping the tcs in a concurrentdictionary against the browser object
        // again, this is pretty dirty but obviously felt like i needed it.
        _browserTasks[_browser] = tcs;

        using (token.Register(() => tcs.TrySetCanceled(), useSynchronizationContext: true))
        {

            // nav to page async
            this._browser.DocumentCompleted += handler;
            try
            {
                if (!string.IsNullOrWhiteSpace(url))
                {
                    this._browser.Navigate(url);                 
                    await tcs.Task; // wait for DocumentCompleted
                }
            }
            finally
            {
                this._browser.DocumentCompleted -= handler;
            }
        }

        // get the root element
        var documentElement = this._browser.Document.GetElementsByTagName("html")[0];

        // poll the current HTML for changes asynchronosly
        var html = documentElement.OuterHtml;
        while (true)
        {
            // wait asynchronously, this will throw if cancellation requested
            await Task.Delay(Properties.Settings.Default.BrowserNavigationWait, token);

            // continue polling if the WebBrowser is still busy
            if (this._browser.IsBusy)
                continue;

            var htmlNow = documentElement.OuterHtml;
            if (html == htmlNow)
                break; // no changes detected, end the poll loop

            html = htmlNow;
        }

        // consider the page fully rendered 
        token.ThrowIfCancellationRequested();

        // remove from task dictionary
        _browserTasks[this._browser] = null;

        return html;
    }

    async void ProcessSiteProfile()
    {
        // now process submission  

        HtmlElement parentForm = null;

        /////////////////
        // parse dom to find the form you're looking for 
        // couple of helpers below
        ///////////////////////

        parentForm = HtmlElementQuery(_browser.Document, "myTextFieldInput");

        var sub = (_browser.Tag as Submission);

        HtmlDocument doc = _browser.Document;

        if (parentForm != null)
        {               
            var elements = parentForm.GetElementsByTagName("input");
            foreach (HtmlElement el in elements)
            {
                // If there's more than one button, you can check the
                // element.InnerHTML to see if it's the one you want
                if (el.GetAttribute("type").ToLower() == "submit")
                {
                    var cts = new CancellationTokenSource(Properties.Settings.Default.BrowserNavigationTimeout); // cancel in 10s

                    var html = await RaiseDynamicEvent(el, "click", cts.Token);
                }
            }
        }
    }

      // used to raise an event with a dom element that would cause the document to change 
    async Task<string> RaiseDynamicEvent(HtmlElement element, string evt, CancellationToken token)
    {
        // navigate and await DocumentCompleted
        var tcs = new TaskCompletionSource<bool>();
        WebBrowserDocumentCompletedEventHandler handler = (s, arg) =>
            tcs.TrySetResult(true);
        _browserTasks[_browser] = tcs;
        using (token.Register(() => tcs.TrySetCanceled(), useSynchronizationContext: true))
        {
            this._browser.DocumentCompleted += handler;

            try
            {
                element.InvokeMember(evt);
                try
                {
                    await tcs.Task; // wait for DocumentCompleted
                }
                catch (TaskCanceledException)
                {
                    // no the end of the world

                }
            }
            finally
            {
                this._browser.DocumentCompleted -= handler;
            }
        }

        // get the root element
        var documentElement = this._browser.Document.GetElementsByTagName("html")[0];

        // poll the current HTML for changes asynchronosly
        var html = documentElement.OuterHtml;
        while (true)
        {
            // wait asynchronously, this will throw if cancellation requested
            await Task.Delay(500, token);

            // continue polling if the WebBrowser is still busy
            if (this._browser.IsBusy)
                continue;

            var htmlNow = documentElement.OuterHtml;
            if (html == htmlNow)
                break; // no changes detected, end the poll loop

            html = htmlNow;
        }

        // consider the page fully rendered 
        token.ThrowIfCancellationRequested();

        // remove from task dictionary
        _browserTasks[this._browser] = null;

        return html;
    }

    // couple of useful helpers

    HtmlElement FindParentByElement(string elementName, HtmlElement element)
    {
        if (element.Parent != null)
        {
            if (element.Parent.TagName.ToLower() == elementName.ToLower())
            {
                return element.Parent;
            }
            else
            {
                return FindParentByElement(elementName, element.Parent);
            }
        }
        else
        {
            return null;
        }
    }

    HtmlElement HtmlElementQuery(HtmlDocument container, string query)
    {
        HtmlElement el = null;
        if (query.StartsWith("#"))
        {
            el = container.GetElementById(query.TrimStart('#'));
        }
        else
        {
            el = container.All[query];
        }

        return el;
    }