Python Programming On Win32

Server-Side COM Again: Excel as a GUI

Excel makes a wonderful frontend for financial applications. We’ve already built a COM server that can handle all of our data and return certain views. There’s a strong case for turning things on their heads and having Excel use Python COM objects in many circumstances. We won’t go through an example here, as we have covered all the necessary techniques in detail, but it’s worth thinking about what’s possible.

Imagine you regularly generate a set of management accounts, including results for the year to date and a forecast a year ahead, and that you extend this with various views of the data. You could easily build an Excel spreadsheet that starts a COM server when opened. Where our VB GUI had to do a double loop over the data to get it into a grid on screen, Excel can insert whole arrays into worksheets in a split second. You can configure sheets within the workbook to display arbitrary views of the data and link charts to these views. Some of these would be user-configurable; for example, selecting an account or customer from a combo box at the top of a sheet could fill the sheet with the relevant data, and a chart below it would be updated automatically.

This is the ideal format in which to deliver numbers to a user; they can immediately start doing their own calculations and building charts or comparisons of the data that interest them.

You could as easily build import applications that allow users to prepare data for import and click a ...