C# WebBrowser Ajax call

Question

I am using a WebBrowser control embedded in a C# WPF .NET4 app. Whenever I press manually the button in a form, the browser hangs on "Your request is being processed" message and nothing happens. If I do the same in full IE browser, the page is processed normally producing the results. What am I missing?

The code behind the button:

<a onclick="startSearch();" href="javascript:void(-1);" name="btnNext" class="btn floatLe noClear btnSubmit btnRight"> 
<span>Continue</span> 
</a>

Raffish

Answer 1

WebBrowser control (both WPF and WinForms versions) behaves in many ways differently from the full IE. You may want to implement Feature Control to bring its behavior as close to IE as possible (particularly, FEATURE_BROWSER_EMULATION), this often solves the script compatibility issues. Here is some code, note that it does not require admin rights to run:

private 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);
    }
}

For example:

private 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.
    SetBrowserFeatureControlKey("FEATURE_AJAX_CONNECTIONEVENTS", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_ENABLE_CLIPCHILDREN_OPTIMIZATION", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_MANAGE_SCRIPT_CIRCULAR_REFS", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_DOMSTORAGE ", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_GPU_RENDERING ", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_IVIEWOBJECTDRAW_DMLT9_WITH_GDI  ", fileName, 0);
    SetBrowserFeatureControlKey("FEATURE_DISABLE_LEGACY_COMPRESSION", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_LOCALMACHINE_LOCKDOWN", fileName, 0);
    SetBrowserFeatureControlKey("FEATURE_BLOCK_LMZ_OBJECT", fileName, 0);
    SetBrowserFeatureControlKey("FEATURE_BLOCK_LMZ_SCRIPT", fileName, 0);
    SetBrowserFeatureControlKey("FEATURE_DISABLE_NAVIGATION_SOUNDS", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_SCRIPTURL_MITIGATION", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_SPELLCHECKING", fileName, 0);
    SetBrowserFeatureControlKey("FEATURE_STATUS_BAR_THROTTLING", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_TABBED_BROWSING", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_VALIDATE_NAVIGATE_URL", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_WEBOC_DOCUMENT_ZOOM", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_WEBOC_POPUPMANAGEMENT", fileName, 0);
    SetBrowserFeatureControlKey("FEATURE_WEBOC_MOVESIZECHILD", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_ADDON_MANAGEMENT", fileName, 0);
    SetBrowserFeatureControlKey("FEATURE_WEBSOCKET", fileName, 1);
    SetBrowserFeatureControlKey("FEATURE_WINDOW_RESTRICTIONS ", fileName, 0);
    SetBrowserFeatureControlKey("FEATURE_XMLHTTP", fileName, 1);
}

private 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 = 11000; // Internet Explorer 11. Webpages containing standards-based !DOCTYPE directives are displayed in IE11 Standards mode. Default value for Internet Explorer 11.
    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;
        case 10:
            mode = 10000; // Internet Explorer 10. Webpages containing standards-based !DOCTYPE directives are displayed in IE10 mode. Default value for Internet Explorer 10.
            break;
        default:
            // use IE11 mode by default
            break;
    }

    return mode;
}

You should come up with your own set of features and register them before WebBrowser has initialized, e.g., in the main form constructor:

public MainWindow()
{
    SetBrowserFeatureControl();

    InitializeComponent();
//...
}

Updated, I currently use and recommend a set of features that can be found here.

Transudate

@Jim, I've added a check for "XDesProc.exe" (VS XAML Designer process), you may want to update your code too. – Transudate

I am not sure if I can continue this thread, but the page I am working on has also an Ajax Popup window which again is not showing in IE embedded browser, but in out of application it works fine? – Raffish

Hmm, hard to tell what's causing it, but I'd again go through the list of all available options and play with those which look related, trying both 1 and 0 values. E.g., FEATURE_AJAX_CONNECTIONEVENTS, FEATURE_WEBOC_POPUPMANAGEMENT, FEATURE_WINDOW_RESTRICTIONS, FEATURE_TABBED_BROWSING etc. Let us know if you find it :) – Transudate

@Noseratio: Great code. Thank you. FYI: SetBrowserFeatureControlKey("FEATURE_NINPUT_LEGACYMODE", fileName, 0) blocks setting mouse cursor by mouse-clicking inside WebBrowser control navigated web pages' text boxes. Windows 8. IE10.0.9200.16750, update: 10.0.12 – Heterochromosome

@ShamilS, thank you, good point, I'll remove it from the answer. – Transudate

No way to do this without reg-edits? This amounts to an ugly hack IMHO. Not a viable solution for me (production machines are locked down). – Culicid

@FizxMike, so locked down that even writing under HKEY_CURRENT_USER is not possible? You don't need HKEY_LOCAL_MACHINE for this. – Transudate

I ended up using CEFSharp for my browser window instead. – Culicid

Answer 2

This works for me:yourWebBrowser.ScriptErrorsSuppressed = true;

Beriosova