semi-unmanaged code with c#


    public delegate void KeyboardHookCaptureHandler(KeyboardHookEventArgs keyboardEvents);
    
    public class KeyboardHookEventArgs : EventArgs {
        
        private Keys _pressedKey;
        private int _pressedKeyCode;    
    
        public Keys PressedKey { get { return _pressedKey; } }
        public int PressedKeyCode { get { return _pressedKeyCode; } }
    
        public KeyboardHookEventArgs(int vkCode) {
            _pressedKey = (Keys)vkCode;
            _pressedKeyCode = vkCode;
        }
    }
    
    public class KeyboardHook {
      
        private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
    
        public event KeyboardHookCaptureHandler KeyIntercepted;
        
        private const int WH_KEYBOARD_LL = 13;
        private const int WM_KEYDOWN = 0x0100;
    
        private LowLevelKeyboardProc _proc;
        private IntPtr _hookID = IntPtr.Zero;
    
        public KeyboardHook() {
            _proc = HookCallback;
            _hookID = SetHook(_proc);
        }
        public bool UnHookKey() {
            return UnhookWindowsHookEx(_hookID);
        }
    
        private IntPtr SetHook(LowLevelKeyboardProc proc) {
            using (Process curProcess = Process.GetCurrentProcess())
            using (ProcessModule curModule = curProcess.MainModule) {
                return SetWindowsHookEx(WH_KEYBOARD_LL, proc,
                    GetModuleHandle(curModule.ModuleName), 0);
            }
        }
    
        private IntPtr HookCallback(
            int nCode, IntPtr wParam, IntPtr lParam) {
            if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN) {
                int vkCode = Marshal.ReadInt32(lParam);          
                KeyboardHookEventArgs keyHookArgs = new KeyboardHookEventArgs(vkCode);
                KeyIntercepted(keyHookArgs);
            }
            return CallNextHookEx(_hookID, nCode, wParam, lParam);
        }
    
    
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr SetWindowsHookEx(int idHook,
            LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);
    
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool UnhookWindowsHookEx(IntPtr hhk);
    
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
            IntPtr wParam, IntPtr lParam);
    
        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr GetModuleHandle(string lpModuleName);
    }

so I have no idea what this code means even though its the core of my program. It hooks a keyboard press event and sends it to my program. Can anyone take there precious time and explain a few things to me. I understand the args class so you can skip that. I am mostly interested in what a **delegate** is, what an **IntPtr** is and the two methods and what they do line by line. 

thanks if anyone has the time

semi-unmanaged code with c#
===



    public delegate void KeyboardHookCaptureHandler(KeyboardHookEventArgs keyboardEvents);
    
    public class KeyboardHookEventArgs : EventArgs {
        
        private Keys _pressedKey;
        private int _pressedKeyCode;    
    
        public Keys PressedKey { get { return _pressedKey; } }
        public int PressedKeyCode { get { return _pressedKeyCode; } }
    
        public KeyboardHookEventArgs(int vkCode) {
            _pressedKey = (Keys)vkCode;
            _pressedKeyCode = vkCode;
        }
    }
    
    public class KeyboardHook {
      
        private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
    
        public event KeyboardHookCaptureHandler KeyIntercepted;
        
        private const int WH_KEYBOARD_LL = 13;
        private const int WM_KEYDOWN = 0x0100;
    
        private LowLevelKeyboardProc _proc;
        private IntPtr _hookID = IntPtr.Zero;
    
        public KeyboardHook() {
            _proc = HookCallback;
            _hookID = SetHook(_proc);
        }
        public bool UnHookKey() {
            return UnhookWindowsHookEx(_hookID);
        }
    
        private IntPtr SetHook(LowLevelKeyboardProc proc) {
            using (Process curProcess = Process.GetCurrentProcess())
            using (ProcessModule curModule = curProcess.MainModule) {
                return SetWindowsHookEx(WH_KEYBOARD_LL, proc,
                    GetModuleHandle(curModule.ModuleName), 0);
            }
        }
    
        private IntPtr HookCallback(
            int nCode, IntPtr wParam, IntPtr lParam) {
            if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN) {
                int vkCode = Marshal.ReadInt32(lParam);          
                KeyboardHookEventArgs keyHookArgs = new KeyboardHookEventArgs(vkCode);
                KeyIntercepted(keyHookArgs);
            }
            return CallNextHookEx(_hookID, nCode, wParam, lParam);
        }
    
    
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr SetWindowsHookEx(int idHook,
            LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);
    
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool UnhookWindowsHookEx(IntPtr hhk);
    
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
            IntPtr wParam, IntPtr lParam);
    
        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr GetModuleHandle(string lpModuleName);
    }

so I have no idea what this code means even though its the core of my program. It hooks a keyboard press event and sends it to my program. Can anyone take there precious time and explain a few things to me. I understand the args class so you can skip that. I am mostly interested in what a **delegate** is, what an **IntPtr** is and the two methods and what they do line by line. 

thanks if anyone has the time
