Detemining newer version of executable in Wix

Question

We have a software that has couple of executables inside. One of the executables is Windows service, and it doesn't change that often, usually we release many updates to the main executable, but the service version is same inside installer.

When service is installed first time or upgraded with newer version, we need to run custom action. We managed to solve first install part, but we don't know how to determine that version we're installing now is newer than one that already exists. Sort of if(newver > oldver) run custom action.

Thank you in advance - Jack

Answer 1

You can try using the upgrade rules of your package. More details here: How to implement WiX installer upgrade?

Rob Mensching (the second answer in the linked thread) shows an example for upgrade rules. You should first familiarize yourself with the Upgrade table and how upgrade rules work. There isn't an easy answer or a quick fix for this in WiX.

Basically, you should have 2 upgrade rules

• the first sets a property when an older version is found
• the second sets another property when a newer version is found

After that you can use the older versions property to condition your custom action. For example, if the property is named OLDERVERSIONFOUND the custom action condition can be:

OLDERVERSIONFOUND 

or something like

OLDERVERSIONFOUND > "1.0.0"

Answer 2

Your best bet is to store the "service" version somewhere in the registry, search for that registry value during upgrade and run your CA if newver > oldver (and the CA should also update said registry value to newver)

Note that Custom Actions are (generally) an admission of failure. I always try to separate out the configuration portion of setup to a pre-install (for sysadmins doing deployment) or post-install (for interactive installations) step - often a separate executable.

Declarative installations with no custom actions are much more reliable - if you can figure out how to rewrite the service so that your custom action is no longer required, you'll be much better off in the long term (this doesn't help when you're under pressure to release now, but it's something to think of for future releases)