C# - How to get Program Files (x86) on Windows 64 bit

Question

I'm using:

FileInfo(
    System.Environment.GetFolderPath(
        System.Environment.SpecialFolder.ProgramFiles) 
    + @"\MyInstalledApp"

In order to determine if a program is detected on a users machine (it's not ideal, but the program I'm looking for is a right old kludge of a MS-DOS application, and I couldn't think of another method).

On Windows XP and 32-bit versions of Windows Vista this works fine. However, on x64 Windows Vista the code returns the x64 Program Files folder, whereas the application is installed in Program Files x86. Is there a way to programatically return the path to Program Files x86 without hard wiring "C:\Program Files (x86)"?

Answer 1

The function below will return the x86 Program Files directory in all of these three Windows configurations:

• 32 bit Windows
• 32 bit program running on 64 bit Windows
• 64 bit program running on 64 bit windows

 

static string ProgramFilesx86()
{
    if( 8 == IntPtr.Size 
        || (!String.IsNullOrEmpty(Environment.GetEnvironmentVariable("PROCESSOR_ARCHITEW6432"))))
    {
        return Environment.GetEnvironmentVariable("ProgramFiles(x86)");
    }

    return Environment.GetEnvironmentVariable("ProgramFiles");
}