[python-win32] thread not posting events woes

[Tim Roberts]

Mike Driscoll wrote:
> Tim Roberts wrote:
>> Jeff Peery wrote:
>>  
>>> I'm having trouble catching events from my multi threaded app. I'm
>>> using wxpython and running several threads under the main wxApp
>>> thread. One of the threads creates a COM object for an OPC server.
>>> I'm using dispatchWithEvents() to get the COM object. When I do this
>>> the server will post an event to the OnDataChange() method in my
>>> application.
>>>  
>>> Everything runs wonderfully when I create the COM object within the
>>> main thread (wxApp). However if I create it from within a sub thread
>>> then the OnDataChange is not being called.     
>>
>> Every thread in a Windows application has its own message queue.  If you
>> create a COM object in a different thread, then its messages will all be
>> delivered to that thread's queue.  However, wxPython is only responding
>> to messages on the main thread, where you created the window.  
>
> I'm probably being naive, but I think using wx.CallAfter or
> wx.CallLater in combination with pubsub
> (http://wiki.wxpython.org/PubSub) would be one of the easiest ways to
> send messages back to your application.

That's good advice in general, but the issue, I think, is that it's not
his app that is generating these events.  He has what I assumed was a
foreign COM object being created in a secondary thread.  He's going to
need to have someone listening to events on that thread to forward them
back to his app's main thread.

-- 
Tim Roberts, timr at probo.com
Providenza & Boekelheide, Inc.