Not getting event arguments in IHTMLElement event handler

Question

I've added a callback to an IHTMLElement instance but when the IDispatch::Invoke is called for the event, there are never any arguments (i.e. the pDispParams->cArgs and pDispParams->cNamedArgs are always 0). For example, I add a callback for an onmouseup event. From what I can tell, a callback for this event is supposed to receive a MouseEvent object. Is that correct? If so, what do I need to do to ensure this happens?

This is using the MSHTML for IE 6 sp2 (or better) on Windows XP SP2.

Answer 1

Events arguments for all DOM events including onmouseup are stored in the parent window's event property (IHTMLWindow2::event)

If you don't already have the parent window cached, IHTMLElement has a document property which returns an IHTMLDocument interface. From that you can query for IHTMLDocument2 which has a parentWindow property. The IHTMLWindow2 that is returned has the event property you're looking for. You should be able to query for the event interface from there.