Keyboard Hook Block ComboKeys C#

namespace BlockShortcuts
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private delegate int LowLevelKeyboardProcDelegate(int nCode, int
           wParam, ref KBDLLHOOKSTRUCT lParam);

        [DllImport("user32.dll", EntryPoint = "SetWindowsHookExA", CharSet = CharSet.Ansi)]
        private static extern int SetWindowsHookEx(
           int idHook,
           LowLevelKeyboardProcDelegate lpfn,
           int hMod,
           int dwThreadId);

        [DllImport("user32.dll")]
        private static extern int UnhookWindowsHookEx(int hHook);

        [DllImport("user32.dll", EntryPoint = "CallNextHookEx", CharSet = CharSet.Ansi)]
        private static extern int CallNextHookEx(
            int hHook, int nCode,
            int wParam, ref KBDLLHOOKSTRUCT lParam);

        const int WH_KEYBOARD_LL = 13;
        private int intLLKey;
        private KBDLLHOOKSTRUCT lParam;

        private struct KBDLLHOOKSTRUCT
        {
            public int vkCode;
            int scanCode;
            public int flags;
            int time;
            int dwExtraInfo;
        }

        private int LowLevelKeyboardProc(
            int nCode, int wParam,
            ref KBDLLHOOKSTRUCT lParam)
        {
            bool blnEat = false;
            switch (wParam)
            {
                case 256:
                case 257:
                case 260:
                case 261:
                    //Alt+Tab, Alt+Esc, Ctrl+Esc, Windows Key
                    if (((lParam.vkCode == 9) && (lParam.flags == 32)) ||
                    ((lParam.vkCode == 27) && (lParam.flags == 32)) || ((lParam.vkCode ==
                    27) && (lParam.flags == 0)) || ((lParam.vkCode == 91) && (lParam.flags
                    == 1)) || ((lParam.vkCode == 92) && (lParam.flags == 1)) || ((true) &&
                    (lParam.flags == 32)))
                    {
                        blnEat = true;
                    }
                    break;
            }

            if (blnEat)
                return 1;
            else return CallNextHookEx(0, nCode, wParam, ref lParam);

        }

        private void KeyboardHook(object sender, EventArgs e)