Python 2.1, COM (Excel), and Threads...

[Mark Hammond]

Adam Karpierz wrote:

> # You have to use pythoncom.CoInitialize and pythoncom.CoUninitialize eg.:

For all threads other than the main thread, correct.

> 
>                import pythoncom
>                pythoncom.CoInitialize()
> 
> 
>>            self.excel = win32com.client.Dispatch("Excel.Application")
> 
> 
>                 pythoncom.CoUninitialize()
> 
> 
>>            self.excel.Visible = 1
>>            k = self.excel.Workbooks.Add()
>>            v = k.Worksheets(1)
>>            v.Cells(1,1).Value = str(self)
>>        except:
>>            import traceback
>>            traceback.print_exc()
> 

This is wrong though.  It should look more like:

              import pythoncom
              pythoncom.CoInitialize()
              self.excel = win32com.client.Dispatch("Excel.Application")

              self.excel.Visible = 1
              k = self.excel.Workbooks.Add()
              v = k.Worksheets(1)
              v.Cells(1,1).Value = str(self)
              # Remove all refs, then uninit.
              self.excel = None
              k = v = None
              pythoncom.CoUninitialize()

ie, CoUninitialize should be the last thing done on a thread, and only 
done after all references to objects created on that thread have been 
destroyed.

Storing a thread-created COM object in your instance (ie, self.excel) is 
a recipe for disaster, but I haven't time to go there now!

Mark.