How to check if it's a silent installation from the custom action DLL?

Question

When my installer is started with msiexec /q /i command line, is there a way to tell that it's a silent installation from my custom action C++ DLL?

PS. I'm using WiX to build my MSI.

Answer 1

The UILevel property of Windows Installer will tell you whether the setup has been launched silently. Four different UI levels are possible:

• INSTALLUILEVEL_NONE - 2 - switch: /qn - Completely silent installation.
• INSTALLUILEVEL_BASIC - 3 - switch: /qb - Simple progress and error handling.
• INSTALLUILEVEL_REDUCED - 4 - switch: /qr - Authored UI, wizard dialogs suppressed.
• INSTALLUILEVEL_FULL - 5 - Authored UI with wizards, progress, errors (/qf).

UILevel may be better used to condition a whole custom action to run or not run depending on what the UILevel is set to? Or you can get its value inside the custom action and change behavior accordingly.

Essential Links:

• Determining UI Level from a Custom Action.
• Common problems with C++ Custom Actions
• Debugging Custom Actions

Further Links:

• How do I add C# methods to an existing large wix script
• Debug C# custom actions
• Determine if this is unattended installation mode?

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UPDATE: From the old Wise Command Line Builder tool, here are some options for the MSI GUI. Note the use of plus and minus to show or hide completion screen for silent install: