C keyboard hook

Hello everyone , I meet you again , I'm your friend, Quan Jun .

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text;

namespace KeyboardHookPro
{
    public class ScanerHook
    {
        public delegate void ScanerDelegate(ScanerCodes codes);
        public event ScanerDelegate ScanerEvent;
        //private const int WM_KEYDOWN = 0x100;//KEYDOWN
        //private const int WM_KEYUP = 0x101;//KEYUP
        //private const int WM_SYSKEYDOWN = 0x104;//SYSKEYDOWN
        //private const int WM_SYSKEYUP = 0x105;//SYSKEYUP

        //private static int HookProc(int nCode, Int32 wParam, IntPtr lParam);
        private int hKeyboardHook = 0;// Declare the initial value of keyboard hook processing 
        private ScanerCodes codes = new ScanerCodes();//13 For keyboard hook 

        // Defined as static , This will not throw a collection exception 
        private static HookProc hookproc;

        private delegate int HookProc(int nCode, int wParam, IntPtr lParam);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        // Set the hook 
        private static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        // Unload hook 
        private static extern bool UnhookWindowsHookEx(int idHook);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        // Continue with the next hook 
        private static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);

        [DllImport("user32", EntryPoint = "GetKeyNameText")]
        private static extern int GetKeyNameText(int IParam, StringBuilder lpBuffer, int nSize);
        [DllImport("user32", EntryPoint = "GetKeyboardState")]
        // Get the status of the key 
        private static extern int GetKeyboardState(byte[] pbKeyState);
        [DllImport("user32", EntryPoint = "ToAscii")]
        //ToAscii Function conversion specifies the virtual key code and the corresponding character or character of the keyboard state 
        private static extern bool ToAscii(int VirtualKey, int ScanCode, byte[] lpKeySate, ref uint lpChar, int uFlags);

        //int VirtualKey //[in]  Specify virtual key code for translation .
        //int uScanCode, // [in]  The key of the specified hardware scan code must be translated into English . This value of higher order bits is the key to setting , If it is （ No pressure ）
        //byte[] lpbKeyState, // [in]  The pointer , With 256 Byte array , Contains the status of the current keyboard . Every element （ byte ） The array of contains a key to the State . If the bytes of higher order bits are a set , The key is to fall （ Press down ）. At low bits , Such as / Result setting indicates , The key is to switch . In this function , Elbow only CAPS LOCK Keys are related . In the switching state NUM Multiple locks and scroll lock keys are ignored .
        //byte[] lpwTransKey, // [out]  The buffer of the pointer receives a translated character or character .
        //uint fuState); // [in] Specifies whether a menu is active. This parameter must be 1 if a menu is active, or 0 otherwise.




        [DllImport("kernel32.dll")]
        // Use WINDOWS API Function instead of the function that gets the current instance , Prevent hook failure 
        public static extern IntPtr GetModuleHandle(string name);

        public bool Start()
        {
            if (hKeyboardHook == 0)
            {
                hookproc = new HookProc(KeyboardHookProc);
                //GetModuleHandle  function   replace  Marshal.GetHINSTANCE  
                // To prevent the  framework4.0 in   Failed to register hook   
                IntPtr modulePtr = GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName);
                //WH_KEYBOARD_LL=13  
                // global hook  WH_KEYBOARD_LL  
                //  hKeyboardHook = SetWindowsHookEx(13, hookproc, Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);  
                hKeyboardHook = SetWindowsHookEx(13, hookproc, modulePtr, 0);
            }
            return (hKeyboardHook != 0);
        }
        public bool Stop()
        {
            if (hKeyboardHook != 0)
            {
                bool retKeyboard = UnhookWindowsHookEx(hKeyboardHook);
                hKeyboardHook = 0;
                return retKeyboard;

            }
            return true;
        }
        private int KeyboardHookProc(int nCode, int wParam, IntPtr lParam)
        {
            EventMsg msg = (EventMsg)Marshal.PtrToStructure(lParam, typeof(EventMsg));
            codes.Add(msg);
            //if (ScanerEvent != null && msg.message == 13 && msg.paramH > 0 && !string.IsNullOrEmpty(codes.Result))
            //{
                ScanerEvent(codes);
            //}
            return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);
        }
        public class ScanerCodes
        {
            private int ts = 100; //  Specify the input interval as 300 Continuous input within milliseconds   
            private List<List<EventMsg>> _keys = new List<List<EventMsg>>();
            private List<int> _keydown = new List<int>();   //  Save key combination state   
            private List<string> _result = new List<string>();  //  Return result set   
            private DateTime _last = DateTime.Now;
            private byte[] _state = new byte[256];
            private string _key = string.Empty;
            private string _cur = string.Empty;
            public EventMsg Event
            {
                get
                {
                    if (_keys.Count == 0)
                    {
                        return new EventMsg();
                    }
                    else
                    {
                        return _keys[_keys.Count - 1][_keys[_keys.Count - 1].Count - 1];
                    }
                }
            }
            public List<int> KeyDowns => _keydown;
            public DateTime LastInput => _last;
            public byte[] KeyboardState => _state;
            public int KeyDownCount => _keydown.Count;
            public string Result
            {
                get
                {
                    if (_result.Count > 0)
                    {
                        return _result[_result.Count - 1].Trim();
                    }
                    else
                    {
                        return null;
                    }
                }
            }
            public string CurrentKey => _key;
            public string CurrentChar => _cur;
            public bool isShift => _keydown.Contains(160);
            public void Add(EventMsg msg)
            {
                #region  Record key information            

                //  Press the button for the first time       
                if (_keys.Count == 0)
                {
                    _keys.Add(new List<EventMsg>());
                    _keys[0].Add(msg);
                    _result.Add(string.Empty);
                }
                //  Press the key when no other key is released   
                else if (_keydown.Count > 0)
                {
                    _keys[_keys.Count - 1].Add(msg);
                }
                //  Press the button in unit time   
                else if ((DateTime.Now - _last).TotalMilliseconds < ts)
                {
                    _keys[_keys.Count - 1].Add(msg);
                }
                //  Input from a new record   
                else
                {
                    _keys.Add(new List<EventMsg>());
                    _keys[_keys.Count - 1].Add(msg);
                    _result.Add(string.Empty);
                }
                #endregion
                _last = DateTime.Now;
                #region  Get keyboard status 
                //  Record the key being pressed   
                if (msg.paramH == 0 && !_keydown.Contains(msg.message))
                {
                    _keydown.Add(msg.message);
                }
                //  Clear the released key   
                if (msg.paramH > 0 && _keydown.Contains(msg.message))
                {
                    _keydown.Remove(msg.message);
                }
                #endregion
                #region  Calculate key information 

                int v = msg.message & 0xff;
                int c = msg.paramL & 0xff;
                StringBuilder strKeyName = new StringBuilder(500);
                if (GetKeyNameText(c * 65536, strKeyName, 255) > 0)
                {
                    _key = strKeyName.ToString().Trim(new char[] { ' ', '\0' });
                    GetKeyboardState(_state);
                    if (_key.Length == 1 && msg.paramH == 0)// && msg.paramH == 0
                    {
                        //  Depending on the keyboard status and shift The cache determines the output character   
                        _cur = ShiftChar(_key, isShift, _state).ToString();
                        _result[_result.Count - 1] += _cur;
                    }
                    //  alternative 

                    // Judgment is +  Force add +
                    else if (_key.Length == 5 && msg.paramH == 0 && msg.paramL == 78 && msg.message == 107)// && msg.paramH == 0
                    {
                        //  Depending on the keyboard status and shift The cache determines the output character   
                        _cur = Convert.ToChar('+').ToString();
                        _result[_result.Count - 1] += _cur;
                    }

                    else
                    {
                        _cur = string.Empty;
                    }
                }
                #endregion
            }
            private char ShiftChar(string k, bool isShiftDown, byte[] state)
            {
                bool capslock = state[0x14] == 1;
                bool numlock = state[0x90] == 1;
                bool scrolllock = state[0x91] == 1;
                bool shiftdown = state[0xa0] == 1;
                char chr = (capslock ? k.ToUpper() : k.ToLower()).ToCharArray()[0];
                if (isShiftDown)
                {
                    if (chr >= 'a' && chr <= 'z')
                    {
                        chr = (char)(chr - 32);
                    }
                    else if (chr >= 'A' && chr <= 'Z')
                    {
                        if (chr == 'Z')
                        {
                            string s = "";
                        }
                        chr = (char)(chr + 32);
                    }
                    else
                    {
                        string s = "`1234567890-=[];',./";
                        string u = "[email protected]#$%^&*()_+{}:\"<>?";
                        if (s.IndexOf(chr) >= 0)
                        {
                            return (u.ToCharArray())[s.IndexOf(chr)];
                        }
                    }
                }
                return chr;
            }
        }
        public struct EventMsg
        {
            public int message;
            public int paramL;
            public int paramH;
            public int Time;
            public int hwnd;
        }
    }
}

Copy

usage

        private ScanerHook listener = new ScanerHook();
        
        public InitHook()
        { 
   
            listener.Start();

            listener.ScanerEvent += Listener_ScanerEvent;// Execute function 

            this.FormClosed += (sender, e) =>
            { 
   
                listener.Stop();
            };
        }


        private void Listener_ScanerEvent(ScanerHook.ScanerCodes codes)
        { 
   
            string msg = codes.Result;// Output here 
        }

Copy

Publisher ： Full stack programmer stack length , Reprint please indicate the source ：https://javaforall.cn/132342.html Link to the original text ：https://javaforall.cn