Changing folder on major upgrade - wix

Question

I have a default directory for installation:
<Directory Id="TARGETDIR" Name="SourceDir">
<Directory Id="ProgramFiles64Folder">
<Directory Id="INSTALLFOLDER" Name="$(var.Manufacturer) $(var.ProductName)"></Directory>
</Directory>
</Directory>
During installation, I allow users to change directory. If a user does change directory during major upgrade, do I have to retrieve the directory manually and set INSTALLFOLDER with actual path or is there a way to detect it automatically somehow?

Answer 1

This is not supported by Windows Installer directly; I think you're looking for the "remember property" pattern. The strategy is:
On initial installation, save the value of INSTALLFOLDER to the registry in a well-known location.
When starting an upgrade, retrieve the value from the registry and use it.
The authoring looks like this:
<!-- Retrieve the property from the registry during AppSearch -->
<Property Id='REMEMBERME'>
<RegistrySearch Id='RememberProperty'
Root='HKCU'
Key='SOFTWARE\My Company\My App'
Name='Remembered'
Type='raw' />
</Property>
<!-- Save the value in the registry for future upgrades -->
<Component Directory='INSTALLFOLDER'>
<RegistryValue Root='HKCU'
Key='SOFTWARE\My Company\My App'
Name='Remembered'
Value='[REMEMBERME]'
Type='string' />
</Component>
Rob Mensching's blog post describes this in much more detail.