64bit OS上の32bitアプリで32bit/64bit両方のProgram Filesフォルダを取得

Program.cs

using System;

namespace ShowProgramFilesFolder
{
    class Program
    {
        static void Main(string[] args)
        {
            // for 32bit
            Console.WriteLine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86));
            // for 64bit
            Console.WriteLine(Environment.ExpandEnvironmentVariables("%ProgramW6432%"));
        }
    }
}

実行結果

C:\Program Files (x86)
C:\Program Files