How to set a check box to “unchecked” from the msiexec command line?

Question

I have an msi (authored with WIX) that has a check box bound to a custom property (call it MY_PROPERTY). I would like to run this msi from the command line, specifying 0 (u

Answer 1

This is how it is "supposed" to work - basically, the property doesn't exist until a user checks the checkbox, then it is "set" (exists). So if you want to do a custom action when a checkbox is checked, you test for the existence of the property as a condition for running the custom action, instead of checking for the value that the custom prop is set to.

I think the best way to handle this from the command line is what you have already mentioned: if you want the checkbox to be selected, specifiy the custom prop on the command line, otherwise, don't and the checkbox will not be selected.

Answer 2

As you've discovered, checkboxes are true (checked) when the property is defined (non-blank) and false (unchecked) when the property is undefined (blank). It sounds like you need to convert an environment 1 or 0 string to a checkbox true/false, where the 1 or 0 is passed in at the command line. Try using a set-property custom action that sets your property to {} (blank) with a condition of when the property is already "0". Schedule it early in both the Install UI and Install Execute sequences.

Late Update: Regarding the need for multiple custom actions to handle this for multiple checkboxes, you have a choice. You can either create multiple set-property actions (benefit: easy to tell what they're doing; cost: many of them), or you can create a single code-based custom action which walks the Checkbox table for a list of properties to convert from 0 to blank (benefit: one action; cost: poorly documented, custom code). A secondary advantage to the latter approach is that you can handle unusual Value settings, such a check box that should set the property to 0 when checked.