How can I tell whether I am on x64 or x86 using .NET?

Question

I'd like to offer my users correct links to an upgraded version of my program based on what platform they're running on, so I need to know whether I'm currently running on an x86 OS or an x64 OS.

The best I've found is using Environment.GetEnvironmentVariable("PROCESSOR_ARCHITECTURE"), but I would think there would be some built-in facility for this?

Answer 1

Environment.Is64BitOperatingSystem and Environment.Is64BitProcess are being introduced in .NET 4. For .NET 2 you'll need to try out some of the other answers.

Answer 2

You can determine a lot via environment variables as used in C# - How to get Program Files (x86) on Windows 64 bit [And this happened to suit me better than Mike's answer which I +1'd as I happen to be interested in finding the Program Files directory name]

Answer 3

Call IsWow64Process to find out if your 32-bit process is running in WOW64 on a 64-bit operating system. You can call GetNativeSystemInfo to find out exactly what it is: the wProcessorArchitecture member of SYSTEM_INFO will be PROCESSOR_ARCHITECTURE_INTEL for 32-bit, PROCESSOR_ARCHITECTURE_AMD64 for x64 and PROCESSOR_ARCHITECTURE_IA64 for Intel's Itanium.

Answer 4

Check just IntPtr.Size . You need to have target platform as AnyCPU.

from here

Answer 5

Check the size of IntPtr with Marshal.SizeOf. 32 bit = 4 bytes, 64 bit = 8 bytes.

Edit: I am not sure this is what you are looking for after reading the question again.