NativeMethods.cs

using System.Runtime.InteropServices;

namespace WindowMinimizer
{
    // Contains all native Windows API definitions and constants required for the application.
    internal static class NativeMethods
    {
        // Hook types and messages
        public const int WH_KEYBOARD_LL = 13;
        public const int WM_KEYDOWN = 0x0100;

        // Window state commands
        public const int SW_MINIMIZE = 6;

        public delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool UnhookWindowsHookEx(IntPtr hhk);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern IntPtr GetModuleHandle(string lpModuleName);

        [DllImport("user32.dll")]
        public static extern IntPtr GetForegroundWindow();

        [DllImport("user32.dll")]
        public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
    }
}