Go back from Webkit to IE render engine

QuickLook.Plugin/QuickLook.Plugin.HtmlViewer/WpfBrowserWrapper.cs

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+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Reflection;
+using System.Runtime.InteropServices;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Forms;
+using System.Windows.Navigation;
+using SHDocVw;
+using HorizontalAlignment = System.Windows.HorizontalAlignment;
+using WebBrowser = System.Windows.Controls.WebBrowser;
+
+namespace QuickLook.Plugin.HtmlViewer
+{
+    /// <summary>
+    ///     Class wraps a Browser (which itself is a bad designed WPF control) and presents itself as
+    ///     a better designed WPF control. For example provides a bindable source property or commands.
+    /// </summary>
+    public class WpfWebBrowserWrapper : ContentControl, IDisposable
+    {
+        private static readonly Guid SidSWebBrowserApp = new Guid("0002DF05-0000-0000-C000-000000000046");
+
+        private WebBrowser _innerBrowser;
+        private bool _loaded;
+        private int _zoom;
+
+        public WpfWebBrowserWrapper()
+        {
+            _innerBrowser = new WebBrowser
+            {
+                HorizontalAlignment = HorizontalAlignment.Stretch,
+                VerticalAlignment = VerticalAlignment.Stretch
+            };
+
+            Content = _innerBrowser;
+            _innerBrowser.Navigated += InnerBrowserNavigated;
+            _innerBrowser.Navigating += InnerBrowserNavigating;
+            _innerBrowser.LoadCompleted += InnerBrowserLoadCompleted;
+            _innerBrowser.Loaded += InnerBrowserLoaded;
+            _innerBrowser.SizeChanged += InnerBrowserSizeChanged;
+        }
+
+        public string Url { get; private set; }
+
+        public int Zoom
+        {
+            get => _zoom;
+            set
+            {
+                _zoom = value;
+                ApplyZoom();
+            }
+        }
+
+
+        // gets the browser control's underlying activeXcontrol. Ready only from within Loaded-event but before loaded Document!
+        // do not use prior loaded event.
+        public InternetExplorer ActiveXControl
+        {
+            get
+            {
+                // this is a brilliant way to access the WebBrowserObject prior to displaying the actual document (eg. Document property)
+                var fiComWebBrowser =
+                    typeof(WebBrowser).GetField("_axIWebBrowser2", BindingFlags.Instance | BindingFlags.NonPublic);
+                if (fiComWebBrowser == null) return null;
+                var objComWebBrowser = fiComWebBrowser.GetValue(_innerBrowser);
+                return objComWebBrowser as InternetExplorer;
+            }
+        }
+
+        public void Dispose()
+        {
+            _innerBrowser.Source = null;
+            _innerBrowser.Dispose();
+            _innerBrowser = null;
+            Content = null;
+        }
+
+        private void InnerBrowserSizeChanged(object sender, SizeChangedEventArgs e)
+        {
+            ApplyZoom();
+        }
+
+        private void InnerBrowserLoaded(object sender, EventArgs e)
+        {
+            // make browser control not silent: allow HTTP-Auth-dialogs. Requery command availability
+            var ie = ActiveXControl;
+            ie.Silent = true;
+        }
+
+        // called when the loading of a web page is done
+        private void InnerBrowserLoadCompleted(object sender, NavigationEventArgs e)
+        {
+            ApplyZoom(); // apply later and not only at changed event, since only works if browser is rendered.
+        }
+
+        // called when the browser started to load and retrieve data.
+        private void InnerBrowserNavigating(object sender, NavigatingCancelEventArgs e)
+        {
+            if (_loaded)
+                e.Cancel = true;
+            _loaded = true;
+        }
+
+        // re query the commands once done navigating.
+        private void InnerBrowserNavigated(object sender, NavigationEventArgs e)
+        {
+            RegisterWindowErrorHanlder_();
+        }
+
+        public void Navigate(string uri)
+        {
+            Url = uri;
+
+            if (_innerBrowser == null)
+                return;
+
+            if (!string.IsNullOrWhiteSpace(uri) && Uri.IsWellFormedUriString(uri, UriKind.Absolute))
+                try
+                {
+                    _innerBrowser.Source = new Uri(uri);
+                }
+                catch (UriFormatException)
+                {
+                    // just don't crash because of a malformed url
+                }
+            else
+                _innerBrowser.Source = null;
+        }
+
+        public void Navigate(Stream stream)
+        {
+            if (_innerBrowser == null)
+                return;
+
+            try
+            {
+                _innerBrowser.NavigateToStream(stream);
+            }
+            catch (Exception)
+            {
+                // ignored
+            }
+        }
+
+        // register script errors handler on DOM - document.window
+        private void RegisterWindowErrorHanlder_()
+        {
+            object parwin = ((dynamic) _innerBrowser.Document).parentWindow;
+            var cookie = new AxHost.ConnectionPointCookie(parwin, new HtmlWindowEvents2Impl(this),
+                typeof(IIntHTMLWindowEvents2));
+            // MemoryLEAK? No: cookie has a Finalize() to Disconnect istelf. We'll rely on that. If disconnected too early, 
+            // though (eg. in LoadCompleted-event) scripts continue to run and can cause error messages to appear again.
+            // --> forget cookie and be happy.
+        }
+
+        private void ApplyZoom()
+        {
+            if (_innerBrowser == null || !_innerBrowser.IsLoaded)
+                return;
+
+            // grab a handle to the underlying ActiveX object
+            IServiceProvider serviceProvider = null;
+            if (_innerBrowser.Document != null)
+                serviceProvider = (IServiceProvider) _innerBrowser.Document;
+            if (serviceProvider == null)
+                return;
+
+            var serviceGuid = SidSWebBrowserApp;
+            var iid = typeof(IWebBrowser2).GUID;
+            var browserInst =
+                (IWebBrowser2) serviceProvider.QueryService(ref serviceGuid, ref iid);
+
+            try
+            {
+                object zoomPercObj = _zoom;
+                // send the zoom command to the ActiveX object
+                browserInst.ExecWB(OLECMDID.OLECMDID_OPTICAL_ZOOM,
+                    OLECMDEXECOPT.OLECMDEXECOPT_DONTPROMPTUSER,
+                    ref zoomPercObj,
+                    IntPtr.Zero);
+            }
+            catch (Exception)
+            {
+                // ignore this dynamic call if it fails.
+            }
+        }
+
+        // needed to implement the Event for script errors
+        [Guid("3050f625-98b5-11cf-bb82-00aa00bdce0b")]
+        [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
+        [TypeLibType(TypeLibTypeFlags.FHidden)]
+        [ComImport]
+        private interface IIntHTMLWindowEvents2
+        {
+            [DispId(1002)]
+            bool onerror(string description, string url, int line);
+        }
+
+        // needed to implement the Event for script errors
+        private class HtmlWindowEvents2Impl : IIntHTMLWindowEvents2
+        {
+            private readonly WpfWebBrowserWrapper _control;
+
+            public HtmlWindowEvents2Impl(WpfWebBrowserWrapper control)
+            {
+                _control = control;
+            }
+
+            // implementation of the onerror Javascript error. Return true to indicate a "Handled" state.
+            public bool onerror(string description, string urlString, int line)
+            {
+                Debug.WriteLine(description + "@" + urlString + ": " + line);
+                // Handled:
+                return true;
+            }
+        }
+
+        // Needed to expose the WebBrowser's underlying ActiveX control for zoom functionality
+        [ComImport]
+        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+        [Guid("6d5140c1-7436-11ce-8034-00aa006009fa")]
+        internal interface IServiceProvider
+        {
+            [return: MarshalAs(UnmanagedType.IUnknown)]
+            object QueryService(ref Guid guidService, ref Guid riid);
+        }
+    }
+}