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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using Windows.Win32.System.Com;
using Windows.Win32.Web.MsHtml;
using static Interop.Mshtml;
namespace System.Windows.Forms;
public sealed partial class HtmlWindow
{
/// <summary>
/// HtmlWindowShim - this is the glue between the DOM eventing mechanisms
/// and our CLR callbacks.
///
/// There are two kinds of events: HTMLWindowEvents2 and IHtmlWindow3.AttachHandler style
/// HTMLWindowEvents2: we create an IConnectionPoint (via ConnectionPointCookie) between us and MSHTML and it calls back
/// on an instance of HTMLWindowEvents2. The HTMLWindowEvents2 class then fires the event.
///
/// IHTMLWindow3.AttachHandler: MSHTML calls back on an HtmlToClrEventProxy that we've created, looking
/// for a method named DISPID=0. For each event that's subscribed, we create
/// a new HtmlToClrEventProxy, detect the callback and fire the corresponding
/// CLR event.
/// </summary>
internal unsafe class HtmlWindowShim : HtmlShim
{
private AxHost.ConnectionPointCookie? _cookie;
private HtmlWindow _htmlWindow;
public HtmlWindowShim(HtmlWindow window)
{
_htmlWindow = window;
}
public override IHTMLWindow2.Interface AssociatedWindow => NativeHtmlWindow;
public IHTMLWindow2.Interface NativeHtmlWindow => (IHTMLWindow2.Interface)_htmlWindow.NativeHtmlWindow.GetManagedObject();
/// Support IHtmlDocument3.AttachHandler
public override void AttachEventHandler(string eventName, EventHandler eventHandler)
{
// IE likes to call back on an IDispatch of DISPID=0 when it has an event,
// the HtmlToClrEventProxy helps us fake out the CLR so that we can call back on
// our EventHandler properly.
HtmlToClrEventProxy proxy = AddEventProxy(eventName, eventHandler);
using var htmlWindow3 = _htmlWindow.GetHtmlWindow<IHTMLWindow3>();
using BSTR name = new(eventName);
using var dispatch = ComHelpers.GetComScope<IDispatch>(proxy);
VARIANT_BOOL result;
htmlWindow3.Value->attachEvent(name, dispatch, &result).ThrowOnFailure();
Debug.Assert(result, "failed to add event");
}
/// Support HTMLWindowEvents2
public override void ConnectToEvents()
{
if (_cookie is null || !_cookie.Connected)
{
_cookie = new AxHost.ConnectionPointCookie(
NativeHtmlWindow,
new HTMLWindowEvents2(_htmlWindow),
typeof(DHTMLWindowEvents2),
throwException: false);
if (!_cookie.Connected)
{
_cookie = null;
}
}
}
/// Support IHTMLWindow3.DetachHandler
public override void DetachEventHandler(string eventName, EventHandler eventHandler)
{
HtmlToClrEventProxy? proxy = RemoveEventProxy(eventHandler);
if (proxy is not null)
{
using var htmlWindow3 = _htmlWindow.GetHtmlWindow<IHTMLWindow3>();
using BSTR name = new(eventName);
using var dispatch = ComHelpers.GetComScope<IDispatch>(proxy);
htmlWindow3.Value->detachEvent(name, dispatch).ThrowOnFailure();
}
}
public override void DisconnectFromEvents()
{
if (_cookie is not null)
{
_cookie.Disconnect();
_cookie = null;
}
}
public void OnWindowUnload() => _htmlWindow?.ShimManager.OnWindowUnloaded(_htmlWindow);
protected override void Dispose(bool disposing)
{
base.Dispose(disposing);
if (disposing)
{
_htmlWindow?.NativeHtmlWindow?.Dispose();
_htmlWindow = null!;
}
}
protected override object GetEventSender() => _htmlWindow;
}
}
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