I've got a legacy application which is implemented in a number of Excel workbooks. It's not something that I have the authority to re-implement, however another application that I do maintain does need to be able to call functions in the Excel workbook.

It's been given a python interface using the Win32Com library. Other processes can call functions in my python package which in turn invokes the functions I need via Win32Com.

Unfortunately COM does not allow me to specify a particular COM process, so at the moment no matter how powerful my server I can only control one instance of Excel at a time on the computer. If I were to try to run more than one instance of excel there would be no way of ensuring that the python layer is bound to a specific Excel instance.

I'd like to be able to run more than 1 of my excel applications on my Windows server concurrently. Is there a way to do this? For example, could I compartmentalize my environment so that I could run as many Excel _ Python combinations as my application will support?

See "Starting a new instance of a COM application" by Tim Golden, also referenced here, which give the hint to use

xl_app = DispatchEx("Excel.Application")

rather than

xl_app = Dispatch("Excel.Application")

to start a separate process. So you should be able to do:

xl_app_1 = DispatchEx("Excel.Application")
xl_app_2 = DispatchEx("Excel.Application")
xl_app_3 = DispatchEx("Excel.Application")

Note that when you're done, to close the app, I've found it's necessary to do:

xl_app.Quit()
xl_app = None

I found the process won't shut down until xl_app = None, that is, the Python COM object's reference count goes to zero.

Note I'm having one remaining problem: while my Python program is running, if I double-click an Excel file in Explorer (at least, on Win2k), it ends up opening the file in the existing Excel process that Python started (which is running hidden), which disrupts the Python program. I haven't yet found a resolution for this.