How can I set the installation directory from a custom action in my wix installer?

Question

I am writing a C# custom action for my wix installer, which will have to set the installation directory.

I've found this question where the asker ends up using SetProperty but that won't work for me because my custom action will read the value from a config file then set it.

Edit: To add some more information, I have a bootstrapper that will call a bunch of MSIs. The bootstrapper will pass a parameter to each MSI, containing a path to an XML config file. The MSI will have a custom action that will read this XML file, and read the install path from it. The MSI is being called with UI suppressed.

How can I accomplish this?

Answer 1

PhilDW is right, I can simply pass it in command line and that will set the install directory. No need to use a custom action for this at all.