A custom task for building WiX under MSBuild (TFS)

My name is Shawn (Hempel) and this is my first submission to the Tranxcoder blog, which is a little ironic since I think it was my idea in the first place. Nonetheless, at least now I am officially “on the board” (and the team can stop razzing me about not posting.)

It seems I’ll be continuing on a running theme of writing about making Team Foundation Server work for us in new and scary ways. If you’re wondering why so much of our blog has centered on that topic, I think it’s two parts: 1) in many ways TFS customization is neither easy or intuitive so as we struggle to make things work, we want to share that with the development community; and 2) since our build process has little to do with the logic in our products, it’s easy to put this stuff out here without worrying about giving away intellectual property. That said, there will probably be more non-build related content as time goes on – we’ll just change variable names to protect the innocent. Alright, on to the good stuff…

As previously mentioned by Richard, we use the WiX toolset to generate Windows Installer binaries (MSI/MSM) for our applications. Personally, I find the recent builds of Votive (WiX’s Visual Studio integration package) to be quite helpful and easy to work with. One of the things it does very well is enable a simple F5 installer build. What it does not do, however, is help you in any way once you decide to graduate from building on the desktop to incorporating an installer build in your TFS processes. Specifically, there will almost certainly be some trouble with the relative and/or absolute paths used in your WiX source files to locate the build outputs to package. Read on to find out how we first solved that problem in a way that made it hard to sleep at night, and subsequently replaced it with a robust, maintainable solution.