Getting back "ResolveIOD" while trying to open HKLM\Software\Microsoft\Windows\CurrentVersion\Installer\ on Windows 7?

I'm trying to get at the UserData registry subkeys on a C# 3.5 application so I can look up the installed location of an external program to start it.

Doing something like this:

RegistryKey installerKey = Registry.LocalMachine.OpenSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Installer");

and then

RegistryKey userDataKey = installerKey.OpenSubKey("UserData");

returns null; if I go back and call installerKey.GetSubKeyNames() to figure out which subkey names are present under Installer it only returns one subkey name: ResolveIOD. I haven't been able to find what only being able to find this key indicates.

regedit does not show the ResolveIOD key being there, and it shows that much more than just that one key is present - UserData, Folders, Secure, etc are all there and not returned by GetSubKeyNames()开发者_运维技巧 either.

This is my first time accessing anything in the Installer section of the registry hive, so I've probably done something wrong. Is there some kind of special permission I have to request in order to read these (probably sensitive, security-wise) keys from a client application, or is this generally not an acceptable thing to do on Windows 7 and I should find an alternative way of figuring out where the program is located?

Because I'm seeing this mentioned on other registry questions: This is running as a 32-bit application on 64-bit Windows.

First, to ensure you are accessing the 64-bit registry rather than the Wow6432Node sandbox, use the RegOpenKeyEx function with KEY_WOW64_64KEY (http://msdn.microsoft.com/en-us/library/ms724878%28v=vs.85%29.aspx) included as one of the access options.

pinvoke.net has a C# example: http://www.pinvoke.net/default.aspx/advapi32/RegOpenKeyEx.html

Also note that with UAC enabled, an unelevated app will, at best, only have read access to HKLM.