一切都很好，但这也应该在env中工作:

PROCESSOR_ARCHITECTURE=x86

..

PROCESSOR_ARCHITECTURE=AMD64

可能太简单了;-)

这是一个基于微软http://1code.codeplex.com/SourceControl/changeset/view/39074#842775代码的解决方案。它使用扩展方法方便代码重用。

下面是一些可能的用法:

bool bIs64BitOS = System.Environment.OSVersion.IsWin64BitOS();

bool bIs64BitProc = System.Diagnostics.Process.GetCurrentProcess().Is64BitProc();

//Hosts the extension methods  
public static class OSHelperTools  
{  
    /// <summary>     
    /// The function determines whether the current operating system is a      
    /// 64-bit operating system.     
    /// </summary>     
    /// <returns>     
    /// The function returns true if the operating system is 64-bit;      
    /// otherwise, it returns false.     
    /// </returns>    
    public static bool IsWin64BitOS(this OperatingSystem os)  
    {  
        if (IntPtr.Size == 8)  
        // 64-bit programs run only on Win64           
            return true;   
        else// 32-bit programs run on both 32-bit and 64-bit Windows     
        {   // Detect whether the current process is a 32-bit process                
            // running on a 64-bit system.               
            return Process.GetCurrentProcess().Is64BitProc();  
        }  
    }  

    /// <summary>  
    /// Checks if the process is 64 bit  
    /// </summary>  
    /// <param name="os"></param>  
    /// <returns>  
    /// The function returns true if the process is 64-bit;        
    /// otherwise, it returns false.  
    /// </returns>    
    public static bool Is64BitProc(this System.Diagnostics.Process p)  
    {  
        // 32-bit programs run on both 32-bit and 64-bit Windows           
        // Detect whether the current process is a 32-bit process                
        // running on a 64-bit system.               
        bool result;  
        return ((DoesWin32MethodExist("kernel32.dll", "IsWow64Process") && IsWow64Process(p.Handle, out result)) && result);  
    }  

    /// <summary>     
    /// The function determins whether a method exists in the export      
    /// table of a certain module.     
    /// </summary>     
    /// <param name="moduleName">The name of the module</param>     
    /// <param name="methodName">The name of the method</param>     
    /// <returns>     
    /// The function returns true if the method specified by methodName      
    /// exists in the export table of the module specified by moduleName.     
    /// </returns>       
    static bool DoesWin32MethodExist(string moduleName, string methodName)  
    {  
        IntPtr moduleHandle = GetModuleHandle(moduleName);  
        if (moduleHandle == IntPtr.Zero)  
            return false;    
        return (GetProcAddress(moduleHandle, methodName) != IntPtr.Zero);   
    }  
    [DllImport("kernel32.dll")]  
    static extern IntPtr GetCurrentProcess();  

    [DllImport("kernel32.dll", CharSet = CharSet.Auto)]  
    static extern IntPtr GetModuleHandle(string moduleName);  

    [DllImport("kernel32", CharSet = CharSet.Auto, SetLastError = true)]  
    static extern IntPtr GetProcAddress(IntPtr hModule, [MarshalAs(UnmanagedType.LPStr)]string procName);  

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]  
    [return: MarshalAs(UnmanagedType.Bool)]  
    static extern bool IsWow64Process(IntPtr hProcess, out bool wow64Process);  
}

我使用以下版本:

    public static bool Is64BitSystem()
    {
        if (Directory.Exists(Environment.GetEnvironmentVariable("Program Files (x86)"))) return true;
        else return false;
    }

更新:正如Joel Coehoorn和其他人建议的那样，从。net Framework 4.0开始，你可以只检查Environment.Is64BitOperatingSystem。

IntPtr。如果在64位Windows上运行32位的. net Framework 2.0, Size将不会返回正确的值(它将返回32位)。

正如微软的Raymond Chen所描述的，你必须首先检查是否运行在64位进程中(我认为在。net中你可以通过检查IntPtr.Size来做到这一点)，如果你运行在32位进程中，你仍然必须调用Win API函数IsWow64Process。如果返回true，则在64位Windows上运行32位进程。

微软的Raymond Chen: 如何以编程方式检测您是否运行在64位Windows上

我的解决方案:

static bool is64BitProcess = (IntPtr.Size == 8);
static bool is64BitOperatingSystem = is64BitProcess || InternalCheckIsWow64();

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

public static bool InternalCheckIsWow64()
{
    if ((Environment.OSVersion.Version.Major == 5 && Environment.OSVersion.Version.Minor >= 1) ||
        Environment.OSVersion.Version.Major >= 6)
    {
        using (Process p = Process.GetCurrentProcess())
        {
            bool retVal;
            if (!IsWow64Process(p.Handle, out retVal))
            {
                return false;
            }
            return retVal;
        }
    }
    else
    {
        return false;
    }
}

考虑到公认的答案非常复杂。还有更简单的方法。我的答案是亚历山德鲁库的。 考虑到64位windows在Program Files (x86)中安装32位应用程序，您可以使用环境变量检查该文件夹是否存在(以弥补不同的本地化)

如。

private bool Is64BitSystem
{
   get
   {
      return Directory.Exists(Environment.ExpandEnvironmentVariables(@"%PROGRAMFILES(X86)%"));
   }
}

这对我来说更快更简单。鉴于我也希望访问基于OS版本的文件夹下的特定路径。

完整的答案是这样的(摘自stefan-mg, ripper234和BobbyShaftoe的答案):

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

    private bool Is64Bit()
    {
        if (IntPtr.Size == 8 || (IntPtr.Size == 4 && Is32BitProcessOn64BitProcessor()))
        {
            return true;
        }
        else
        {
            return false;
        }
    }

    private bool Is32BitProcessOn64BitProcessor()
    {
        bool retVal;

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

        return retVal;
    } 

首先检查您是否处于64位进程中。如果不是，检查32位进程是否是Wow64Process。