Inspired by a new Excel add-in developer, I’ve decided to create a list of Excel developer resources. It’s sparse now, but I will upate it periodically.

Books

I’ve only found 2 that are even worth mentioning.

• Professional Excel Development by Bullen, Bovey, and Green is the best book on the market for .xla and COM add-ins.
• Microsoft .NET Development for Microsoft Office by Whitechapel is the best I’ve found book for .NET Office development.

Sites

• http://www.fontstuff.com/ has a useful MS Office version survey. The survey is skewed by the nature of the people who visit his site, but it’s useful nonetheless. Bottom line: don’t jump through hoops to support Excel 97. It’s just not worth the effort.
• Sign up for kbAlertz. As the names implies, you get Microsoft Knowledge Base alerts for selected products.
• There are a number of decent forums. Maybe I’ll get around to posting some of them.

Listing on Directories

• You must get listed on Microsoft Office Marketplace. The site gets 50 million unique visitors per month and can be a considerable source of traffic. You can list on their the international sites as well.
• It’s also worth it to get listed at download.com. Products listed at download.com show up in the Windows Catalog faster. You may never have noticed the Windows Catalog in your Start menu before, but it’s there at the top of the All Programs menu.
• Cool tip: choose your product description carefully. If a user types in one of your keywords in the Excel help search box, your software will be listed in the results, as shown below. To be honest I’m not sure whether it’s being in the Windows Catalog or Microsoft Office Marketplace that gets you listed in the help file, but do both anyway.

• Most speciality directories for Excel add-ins do affiliate sales and require that you have an account setup through RegNow. The problems with RegNow are: (1) They want to be your only payment processor to qualify for the low processing fee. You must set up an subdomain that cannot reach the main domain if you wish to offer another payment processing option to non-affiliate sales. (2) RegNow tacks on a Download Protection Insurance option for a $6.95 fee. It’s opt-out, not opt-in so it’s really sleazy.

  Are they worth it? Probably. A lot of them get a fair amount of traffic. ExcelBusinessTools does not require RegNow, and they drive 400-500 visitors per month to my site. Ozgrid.com, on the other hand, does require RegNow but they get about 6 times more traffic than ExcelBusinessTools. So I will probably bite the bullet and set up a separate subdomain and build for RegNow.

  (Update: For some reason the owner of ExcelBusinessTools.com started redirecting their traffic to a new domain, spreadsheet-solutions.com. After they did, the traffic coming into BreezeTree dropped to a trickle. It’s too bad, really.)

• Some download sites do not allow add-ins. If it makes sense for your application you might consider a standalone application that launches Excel.

Rules of Thumb

• Develop in the oldest version of Excel that you plan to support.
• If you’re doing COM Add-ins develop using early binding and switch to late binding for your build. This may result in marginally slower performance but will result in less version compatibility problems.
• If you’re doing COM and sinking Excel events, ignore the last item. You must use early binding.
• The earliest version of Excel that supports COM add-ins is Excel 2000.
• Use Excel’s VBA Editor (aka VBE) to do Unit Testing. Most code that interacts directly with the spreadsheet can be broken out and setup as a Sub or Function in the VBE. I keep a test development file with any necessary support code, and I typically create three methods: (1) the Sub or Function in development, (2) the test function to call #1, and (3) a Sub to restore the spreadsheet to its original condition. The first two are obvious, but the third one may not be and is a real time saver.

Downsides

• Because you are playing in someone else’s yard, you end up having to scoop their poop. Because your program operates within Excel, the customer is likely to view any Excel-related problems as a support issue to contact you with.

[Last Update: 8-31-2006]