Reading the registry and Wow6432Node key

Question

I have some code that reads the registry and looks for a value in HKEY_LOCAL_MACHINE\Software\App\ but when running on 64-bit versions of Windows the value is under HKEY_LOCAL_MACHINE\Software\Wow6432Node\App\.

How should I best approach this? Do I need a 64-bit installer or should I rewrite my code to detect both places?

Answer 1

On an x64 machine, here is an example of how to access the 32-bit view of the registry:

using (var view32 = RegistryKey.OpenBaseKey(RegistryHive.CurrentUser,                                             RegistryView.Registry32)) {   using (var clsid32 = view32.OpenSubKey(@"Software\Classes\CLSID\", false))   {     // actually accessing Wow6432Node    } } 

... as compared to...

using (var view64 = RegistryKey.OpenBaseKey(RegistryHive.CurrentUser,                                             RegistryView.Registry64)) {   using (var clsid64 = view64.OpenSubKey(@"Software\Classes\CLSID\", true))   {     ....   } } 

Answer 2

If you mark you C# program as x86 (and not Any CPU) then it will see HKEY_LOCAL_MACHINE\Software\Wow6432Node\App as HKEY_LOCAL_MACHINE\Software\App\.

A .NET program for Any CPU will run as a 64-bit process if 64-bit .NET is installed. The 32-bit registry is under the Wow6432Node for 64-bit programs.