Windows服务从虚拟注册表中读取

Question

Please correct me if I'm wrong on this, as I'm certain I read it somewhere: Registry virtualization is disabled for Windows Services. Also, virtualization is disabled for x64 binaries.

I have a windows service written in C# that needs to load a value from HKEY_LOCAL_MACHINE\\SOFTWARE. When I compile the service as x86 and start it, it fails to read the value. When I compile the same code as x64 and start it, it reads the value just fine. I want my service to be able to run on x86 machines in addition to x64 machines, but it needs to also be able to read this value. How do I get my windows service to read the value non-virtualized?

Answer 1

Registry virtualization is disabled for Windows Services. Also, virtualization is disabled for x64 binaries.

Yes, you're right, it's disabled for 64 bit processes and for " processes that are not interactive, such as services ".

Take a look to my previous post here on SO for some details about registry views. Please do not confuse views with virtualization . They're different. Views are needed to isolate 32-bit application from 64-bit applications.

In C# you can do the same simply asking the OS to open the 64 bit version of the registry:

RegistryKey baseKey = RegistryKey.OpenBaseKey(
    RegistryHive.LocalMachine, RegistryView.Registry64);
RegistryKey key = baseKey.OpenSubKey("Software", false);
object value = key.GetValue("");

If your application/service will run in a 32-bit machine you'll always get the normal registry even if you ask for RegistryView.Registry64 . When running in a 64-bit machine you'll always get the normal version of the registry (= 64-bit version).

Side question: why do you need to compile your application as X86 or X64? Can't simply keep AnyCPU?

Virtualization has a different purpose and it's not intended to separate the registry from 32 bit applications but to increase compatibility with legacy applications, we all hope that a 64 bit native application will use the registry in the correct way. To access the non-virtualized version of the registry you have to open the registry key using REG_KEY_DONT_VIRTUALIZE flag. It's not possible to use this flag with Microsoft.Win32 classes so you have to DllImport them and P/Invoke.