How to Detect 64bit OS/Process on .NET 2.0 to 3.5

Introduction

Simple function to detect:

• Operation System is 64 bit?
• Process is 64bit?

The Code

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

public static class Misc
{
    [DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool IsWow64Process([In] IntPtr hProcess, [Out] out bool lpSystemInfo);

    /// <summary>
    /// Detect Operation System is 64bit
    /// </summary>
    /// <returns></returns>
    public static bool Is64BitOS()
    {
        using (Process p = Process.GetCurrentProcess())
        {
            bool retVal;
            return (IntPtr.Size == 8 ||
                    (IsWow64Process != null && IntPtr.Size == 4 &&
                     IsWow64Process(p.Handle, out retVal) && retVal)
                   );
        }
    }

    /// <summary>
    /// Detect Process is 64bit
    /// </summary>
    /// <returns></returns>
    public static bool Is64BitProc()
    {
        return (IntPtr.Size == 8);
    }
}

How to Use

if(Misc.Is64BitOS())
{
    Console.WriteLine("Os is 64bit");
}
else
{
    Console.WriteLinve("Os is not 64bit"); // means 32bit at 2015-02-03 :)
}

if(Misc.Is64BitProc())
{
    Console.WriteLine("Process is 64bit");
}

Notes

IntPtr.Size is 8 in 64bit Process and 4 in 32bit Process.

"WOW64 is the x86 emulator that allows 32-bit Windows-based applications to run seamlessly on 64-bit Windows."
IsWow64Process detects 32bit process runs in Wow64.

.NET 4, and .NET 4.5

System.Environment.Is64BitOperatingSystem for checking OS

System.Environment.Is64BitProcess for checking Process