"SystemFolder" in WIX and C#

Question

An installer I have created with WiX installs a DLL using the SystemFolder variable, as well as a C# app into another folder. I want to directly reference the DLL from the app. Do I need to look up registry keys to find where the SystemFolder is?

Answer 1

No, you don't need to query the registry. Windows Installer has a series of built-in properties that automatically resolve to special well known locations such as SystemFolder.

See System Folder Properties for more general information. For WiX, just create a Directory element as a direct child of the TARGETDIR Directory element:

<Directory Id="TARGETDIR" Name="SourceDir">
  <Directory Id="SystemFolder" Name="SystemFolder" />
</Directory>

If you already know this and want to know how to reference the DLL from C#, SystemFolder is in the search path so I'm not sure why you'd have to. If it was me, I'd compile the C# as x86 ( AnyCPU is somewhat out of vogue now ) and use:

string myDllPath = Path.Combine( System.Environment.SystemDirectory, "my.dll" );