How to set the UILevel to INSTALLUILEVEL_BASIC when performing a major upgrade?

Question

I'm building an installation/upgrade package with WiX. I'm using the WixUI_InstallDir dialog set.

What I want to do is to have a fully automated installation (no wizard) when performing a major upgrade of the installed product.

Is it possible to:

• conditionally change the value of UILevel during the installation? (INSTALLUILEVEL_FULL / INSTALLUILEVEL_BASIC)
• conditionally change the dialog set? (WixUI_InstallDir / WixUI_Minimal)

Or is there a better way to do this?

Answer 1

In BasicUI the UI Sequence isn't run. The problem is you don't know if you are a MajorUpgrade until FindRelatedProducts runs and finds a related ProductCode. I think the best you could do is put a condition on your WelcomeDlg to not be displayed when it's a Major Upgrade.