如何以编程方式确定特定进程是32位还是64位

One of the more interesting ways I've seen is this:

if (IntPtr.Size == 4)
{
// 32-bit
}
else if (IntPtr.Size == 8)
{
// 64-bit
}
else
{
// The future is now!
}

To find out if OTHER processes are running in the 64-bit emulator (WOW64), use this code:

namespace Is64Bit
{
using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.InteropServices;


internal static class Program
{
private static void Main()
{
foreach (var p in Process.GetProcesses())
{
try
{
Console.WriteLine(p.ProcessName + " is " + (p.IsWin64Emulator() ? string.Empty : "not ") + "32-bit");
}
catch (Win32Exception ex)
{
if (ex.NativeErrorCode != 0x00000005)
{
throw;
}
}
}


Console.ReadLine();
}


private static bool IsWin64Emulator(this Process process)
{
if ((Environment.OSVersion.Version.Major > 5)
|| ((Environment.OSVersion.Version.Major == 5) && (Environment.OSVersion.Version.Minor >= 1)))
{
bool retVal;


return NativeMethods.IsWow64Process(process.Handle, out retVal) && retVal;
}


return false; // not on 64-bit Windows Emulator
}
}


internal static class NativeMethods
{
[DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern bool IsWow64Process([In] IntPtr process, [Out] out bool wow64Process);
}
}

You can check the size of a pointer to determine if it's 32bits or 64bits.

int bits = IntPtr.Size * 8;
Console.WriteLine( "{0}-bit", bits );
Console.ReadLine();

If you're using .Net 4.0, it's a one-liner for the current process:

Environment.Is64BitProcess

See Environment.Is64BitProcessProperty (MSDN).

I like to use this:

string e = Environment.Is64BitOperatingSystem

This way if I need to locate or verify a file I can easily write:

string e = Environment.Is64BitOperatingSystem


// If 64 bit locate the 32 bit folder
? @"C:\Program Files (x86)\"


// Else 32 bit
: @"C:\Program Files\";

Here is the one line check.

bool is64Bit = IntPtr.Size == 8;

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


public static bool Is64Bit()
{
bool retVal;


IsWow64Process(Process.GetCurrentProcess().Handle, out retVal);


return retVal;
}

The selected answer is incorrect as it doesn't do what was asked. It checks if a process is a x86 process running on x64 OS instead; so it will return "false" for a x64 process on x64 OS.
Also, it doesn't handle errors correctly.

Here is a more correct method:

internal static class NativeMethods
{
// see https://msdn.microsoft.com/en-us/library/windows/desktop/ms684139%28v=vs.85%29.aspx
public static bool Is64Bit(Process process)
{
if (!Environment.Is64BitOperatingSystem)
return false;
// if this method is not available in your version of .NET, use GetNativeSystemInfo via P/Invoke instead


bool isWow64;
if (!IsWow64Process(process.Handle, out isWow64))
throw new Win32Exception();
return !isWow64;
}


[DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool IsWow64Process([In] IntPtr process, [Out] out bool wow64Process);
}