C # WebBrowser Control - submitting form does not work using InvokeMember ("Click")

Question

I am working on an automated testing script and am using a WebBrowser control. I am trying to present the following HTML and testing when the user accepts the terms of service:

<form action="http://post.dev.dealerconnextion/k/6hRbDTwn4xGVl2MHITQsBw/hrshq" method="post"> <input name="StepCheck" value="U2FsdGVkX18zMTk5MzE5OUgFyFgD3V5yf5Rwbtfhf3gjdH4KSx4hqj4vkrw7K6e-" type="hidden"> <button type="submit" name="continue" value="y">ACCEPT the terms of use</button> <button type="submit" name="continue" value="n">DECLINE the terms of use</button> </form> // Terms of Use Information <form action="http://post.dev.dealerconnextion/k/6hRbDTwn4xGVl2MHITQsBw/hrshq" method="post"> <input name="StepCheck" value="U2FsdGVkX18zMTk5MzE5OUgFyFgD3V5yf5Rwbtfhf3gjdH4KSx4hqj4vkrw7K6e-" type="hidden"> <button type="submit" name="continue" value="y">ACCEPT the terms of use</button> <button type="submit" name="continue" value="n">DECLINE the terms of use</button> </form> 

Here is the code in C # but does not submit the form.

  HtmlElementCollection el = webBrowser.Document.GetElementsByTagName("button"); foreach (HtmlElement btn in el) { if (btn.InnerText == "ACCEPT the terms of use") { btn.InvokeMember("Click"); } } 

Any help would be greatly appreciated. Thank.

Answer 1

The following code works for me using the real-time action URL from comments verified with IE10. Try it as it is. If it works for you too, feel free to use it as a template for web automation tasks. A few points:

• FEATURE_BROWSER_EMULATION is used to ensure that the WebBrowser behaves the same as a standalone IE browser (or as close as possible). This is a must for almost any WebBrowser based project. I believe that what should help solve the original problem is on your side.

• Asynchronous code is used to increase the reliability of automation logic, add support and cancel timeouts, and provide a natural linear code stream (using async/await ).

C # :

 using Microsoft.Win32; using System; using System.Diagnostics; using System.Linq; using System.Threading; using System.Threading.Tasks; using System.Windows.Forms; namespace WebAutomation { // http://stackoverflow.com/q/19044659/1768303 public partial class MainForm : Form { WebBrowser webBrowser; // non-deterministic delay to let AJAX code run const int AJAX_DELAY = 1000; // keep track of the main automation task CancellationTokenSource mainCts; Task mainTask = null; public MainForm() { SetBrowserFeatureControl(); // set FEATURE_BROWSER_EMULATION first InitializeComponent(); InitBrowser(); this.Load += (s, e) => { // start the automation when form is loaded // timeout the whole automation task in 30s mainCts = new CancellationTokenSource(30000); mainTask = DoAutomationAsync(mainCts.Token).ContinueWith((completedTask) => { Trace.WriteLine(String.Format("Automation task status: {0}", completedTask.Status.ToString())); }, TaskScheduler.FromCurrentSynchronizationContext()); }; this.FormClosing += (s, e) => { // cancel the automation if form closes if (this.mainTask != null && !this.mainTask.IsCompleted) mainCts.Cancel(); }; } // create a WebBrowser instance (could use an existing one) void InitBrowser() { this.webBrowser = new WebBrowser(); this.webBrowser.Dock = DockStyle.Fill; this.Controls.Add(this.webBrowser); this.webBrowser.Visible = true; } // the main automation logic async Task DoAutomationAsync(CancellationToken ct) { await NavigateAsync(ct, () => this.webBrowser.Navigate("http://localhost:81/test.html"), 10000); // timeout in 10s // page loaded, log the page HTML Trace.WriteLine(GetBrowserDocumentHtml()); // do the DOM automation HtmlElementCollection all = webBrowser.Document.GetElementsByTagName("button"); // throw if none or more than one element found HtmlElement btn = all.Cast<HtmlElement>().Single( el => el.InnerHtml == "ACCEPT the terms of use"); ct.ThrowIfCancellationRequested(); // simulate a click which causes navigation await NavigateAsync(ct, () => btn.InvokeMember("click"), 10000); // timeout in 10s // form submitted and new page loaded, log the page HTML Trace.WriteLine(GetBrowserDocumentHtml()); // could continue with another NavigateAsync // othrwise, the automation session completed } // Get the full HTML content of the document string GetBrowserDocumentHtml() { return this.webBrowser.Document.GetElementsByTagName("html")[0].OuterHtml; } // Async navigation async Task NavigateAsync(CancellationToken ct, Action startNavigation, int timeout = Timeout.Infinite) { var onloadTcs = new TaskCompletionSource<bool>(); EventHandler onloadEventHandler = null; WebBrowserDocumentCompletedEventHandler documentCompletedHandler = delegate { // DocumentCompleted may be called several time for the same page, // beacuse of frames if (onloadEventHandler != null || onloadTcs == null || onloadTcs.Task.IsCompleted) return; // handle DOM onload event to make sure the document is fully loaded onloadEventHandler = (s, e) => onloadTcs.TrySetResult(true); this.webBrowser.Document.Window.AttachEventHandler("onload", onloadEventHandler); }; using (var cts = CancellationTokenSource.CreateLinkedTokenSource(ct)) { if (timeout != Timeout.Infinite) cts.CancelAfter(Timeout.Infinite); using (cts.Token.Register(() => onloadTcs.TrySetCanceled(), useSynchronizationContext: true)) { this.webBrowser.DocumentCompleted += documentCompletedHandler; try { startNavigation(); // wait for DOM onload, throw if cancelled await onloadTcs.Task; ct.ThrowIfCancellationRequested(); // let AJAX code run, throw if cancelled await Task.Delay(AJAX_DELAY, ct); } finally { this.webBrowser.DocumentCompleted -= documentCompletedHandler; if (onloadEventHandler != null) this.webBrowser.Document.Window.DetachEventHandler("onload", onloadEventHandler); } } } } // Browser feature conntrol void SetBrowserFeatureControl() { // http://msdn.microsoft.com/en-us/library/ee330720(v=vs.85).aspx // FeatureControl settings are per-process var fileName = System.IO.Path.GetFileName(Process.GetCurrentProcess().MainModule.FileName); // make the control is not running inside Visual Studio Designer if (String.Compare(fileName, "devenv.exe", true) == 0 || String.Compare(fileName, "XDesProc.exe", true) == 0) return; SetBrowserFeatureControlKey("FEATURE_BROWSER_EMULATION", fileName, GetBrowserEmulationMode()); // Webpages containing standards-based !DOCTYPE directives are displayed in IE10 Standards mode. } void SetBrowserFeatureControlKey(string feature, string appName, uint value) { using (var key = Registry.CurrentUser.CreateSubKey( String.Concat(@"Software\Microsoft\Internet Explorer\Main\FeatureControl\", feature), RegistryKeyPermissionCheck.ReadWriteSubTree)) { key.SetValue(appName, (UInt32)value, RegistryValueKind.DWord); } } UInt32 GetBrowserEmulationMode() { int browserVersion = 7; using (var ieKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Internet Explorer", RegistryKeyPermissionCheck.ReadSubTree, System.Security.AccessControl.RegistryRights.QueryValues)) { var version = ieKey.GetValue("svcVersion"); if (null == version) { version = ieKey.GetValue("Version"); if (null == version) throw new ApplicationException("Microsoft Internet Explorer is required!"); } int.TryParse(version.ToString().Split('.')[0], out browserVersion); } UInt32 mode = 10000; // Internet Explorer 10. Webpages containing standards-based !DOCTYPE directives are displayed in IE10 Standards mode. Default value for Internet Explorer 10. switch (browserVersion) { case 7: mode = 7000; // Webpages containing standards-based !DOCTYPE directives are displayed in IE7 Standards mode. Default value for applications hosting the WebBrowser Control. break; case 8: mode = 8000; // Webpages containing standards-based !DOCTYPE directives are displayed in IE8 mode. Default value for Internet Explorer 8 break; case 9: mode = 9000; // Internet Explorer 9. Webpages containing standards-based !DOCTYPE directives are displayed in IE9 mode. Default value for Internet Explorer 9. break; default: // use IE10 mode by default break; } return mode; } } } 

Content http://localhost:81/test.html :

 <!DOCTYPE html> <head> <meta http-equiv="X-UA-Compatible" content="IE=edge"/> </head> <body> <form action="<the URL from OP comments>" method="post"> <input name="StepCheck" value="U2FsdGVkX18zMTk5MzE5OUgFyFgD3V5yf5Rwbtfhf3gjdH4KSx4hqj4vkrw7K6e-" type="hidden"> <button type="submit" name="continue" value="y">ACCEPT the terms of use</button> <button type="submit" name="continue" value="n">DECLINE the terms of use</button> </form> </body> 

Answer 2

This works for me as follows. let it be useful to someone.

First, I create an event handler for the button element when I get focus. After all other elements of the form are filled with the corresponding values, you should select the button as follows:

 HtmlElement xUsername = xDoc.GetElementById("username_txt"); HtmlElement xPassword = xDoc.GetElementById("password_txt"); HtmlElement btnSubmit = xDoc.GetElementById("btnSubmit"); if (xUsername != null && xPassword != null && btnSubmit != null) { xUsername.SetAttribute("value", "testUserName"); xPassword.SetAttribute("value", "123456789"); btnSubmit.GotFocus += BtnSubmit_GotFocus; btnSubmit.Focus(); } 

Then the implementation of the event handler will look like this:

 private void BtnSubmit_GotFocus(object sender, HtmlElementEventArgs e) { var btnSubmit = sender as HtmlElement; btnSubmit.RaiseEvent("onclick"); btnSubmit.InvokeMember("click"); }