I have a plugin which has a content stream pushed to it from an external service which I then draw into a PluginWindowlessWin.
I maintain a reference to the PluginWindowlessWin object so that I can call Invalidate() when new content arrives. However, in certain circumstances (e.g., plugin object removed from the page), the PluginWindowlessWin object is deleted without notifying my plugin. Thus, I end up calling Invalidate() on a bad pointer and crashing.
How can I continue to notify the browser of updates so it will continue to send refresh events - through Invalidate() calls or otherwise - without relying on objects that may be silently deleted?
When using a windowless plugin, you can't draw except when the browser requests it. Sounds like you have that part. You can ask the browser to request a draw by calling InvalidateWindow on the PluginWindowlessWin.
Once AttachedEvent is called on your plugin, PluginWindowlessWin will be available; you can even save the reference if you want. However, you need to release it when DetachedEvent is called.