How does the setup bootstrapper detect if prerequisites are installed?

Trying to solve this problem.

I would like to learn how the bootstrapper detects if prerequisites (specifically .NET 3.5) are installed.

According to this reference, a way to detect if .NET is installed is to check the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5

Using process monitor, I have inspected registry queries done by the bootstrapper (setup.exe) and it did not show any access to this registry key.

Does anybody know how the bootstrapper determines whethe开发者_开发知识库r the prerequisites are installed on the target system?

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Prerequisite packages for the msbuild GenerateBootStrapper packages are defined as XML files. The schema of those XML files is documented here. Take a look at the "InstallChecks" element to get an idea of what sort of checks are possible.

Curiously enough, I could not find such install checks in the prerequisite package for .NET 3.5. You can find this package in the windows SDK folder (C:\Program Files\Microsoft SDKs\Windows), along with the other predefined bootstrapper packages.