Dynamically set install dir in WiX V4 from environment variable

[domischell]

Hi,
I want to install a component under a directory that is defined at installation-time by an environment variable on the machine, for example SOME_ENV_VAR. I found a question on stackoverflow that said to use the following contruct in my Package.wxs:

<Directory Id="FolderFromEnvVar">
    <Directory Id="InstallMeHere" Name="Subfolder" />
</Directory>
<SetDirectory Id="FolderFromEnvVar" Value="[%SOME_ENV_VAR]" Sequence="first" />

I consume this in my XXXComponents.wxs like so

<Wix>
    <Fragment>
        <Component Id="XXXComponents" Guid="someGUID" Directory="InstallMeHere">
            <File Source=...

I open an elevated command shell, set the enviroment variable and run msiexec with my installer

set SOME_ENV_VAR="C:\Program Files\Here\Please"
msiexec /i Setup\bin\x64\Debug\Setup.msi /lv %temp%\Installer.txt /quiet

And for some reason the files are installed to F:
The log says

MSI (s) (A8:18) [17:56:27:873]: PROPERTY CHANGE: Adding FolderFromEnvVar property. Its value is 'F:\'.
MSI (s) (A8:18) [17:56:27:873]: PROPERTY CHANGE: Adding InstallMeHere property. Its value is 'F:\Subfolder\'.

Why is it set to F:\ instead of the value in SOME_ENV_VAR? Any help would be highly appreciated.
Dom

[robmen]

My first guess would be that your set command is only affecting the local command-prompt and not getting to the server side of the Windows Installer. Try setting the variable in the System on Windows and see if that makes a difference.

If not, dig through the log file a bit more to see what the Windows Installer thinks that variable is. If the env var doesn't show up in the log, try using a SetProperty to get a property change log message with the value.

[domischell]

Thanks for the hint. The MSI installation indeed doesn't seem to be executed under the current shell and therefore can't see the environment variable that I have set with set. It only sees them if specified under the System or User context in the "Advanced System Settings -> Environment Variables...". I have to use setx instead of set.

> setx SOME_USER_VAR "C:\Program Files\Here\Please"

SUCCESS: Specified value was saved.
> msiexec /i Setup\bin\x64\Debug\Setup.msi /lv %temp%\Installer.txt /quiet

Now I see the change in the log and the files are installed where I expect them to be

MSI (s) (CC:24) [17:30:39:165]: PROPERTY CHANGE: Modifying FolderFromEnvVar property. Its current value is 'F:\'. Its new value: 'C:\Program Files\Here\Please\'.

Thanks,
Dom