C#如何监听键盘Caps lock键按下事件？

[Aspirant_Happy]

我想知道在密码文本输入框，按下Caps lock键，我想要监听到这个事件，做出响应，而不是单纯的检测Caps lock的状态，Caps lock键对应的ASC2码是20，可是当键盘按下时却监听不到，结果没有响应，假设我监听其他键按下时却可以，请问这是为什么呀，是因为有些键不能直接获取对应的ASC整型码吗？请大神指点该怎么做

[ERDY1337]

keydown是按下一个按键，比如大小写，小键盘锁等 keypress是键入一个字符，比如字母键，数字键 Capslock是属于第一种，不会键入字符的，所以keypress不行

[lzhdim]

用 KeyDown 。。。

[desperaso]

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace Test_7
{
    public class KeyRecord
    {
        public List<string> _Record = new List<string>();
        public RichTextBox r1 = new RichTextBox() { Size = new Size(400, 300) };

        private const int WM_KEYDOWN = 0x100;
        private const int WM_KEYUP = 0x101;
        private const int WM_SYSKEYDOWN = 0x104;
        private const int WM_SYSKEYUP = 0x105;
        public event KeyEventHandler OnKeyDownEvent;
        public event KeyEventHandler OnKeyUpEvent;
        public event KeyPressEventHandler OnKeyPressEvent;
        static int hKeyboardHook = 0;
        public const int WH_KEYBOARD_LL = 13;
        HookProc KeyboardHookProcedure;
        [StructLayout(LayoutKind.Sequential)]
        public class KeyboardHookStruct
        {
            public int vkCode;
            public int scanCode;
            public int flags;
            public int time;
            public int dwExtraInfo;
        }
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern bool UnhookWindowsHookEx(int idHook);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);
        [DllImport("user32")]
        public static extern int GetKeyboardState(byte[] pbKeyState);
        public delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);
        public KeyRecord()
        {
            this.OnKeyPressEvent += new KeyPressEventHandler(KeyBordHook_OnKeyPressEvent);
            Start();
        }
        public void Start()
        {
            if (hKeyboardHook == 0)
            {
                KeyboardHookProcedure = new HookProc(KeyboardHookProc);
                Module m = Assembly.GetExecutingAssembly().GetModules()[0];
                IntPtr itp = Marshal.GetHINSTANCE(m);
                hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyboardHookProcedure, itp, 0);
                if (hKeyboardHook == 0) Stop();
            }
        }
        public void Stop()
        {
            bool retKeyboard = true;
            if (hKeyboardHook != 0)
            {
                retKeyboard = UnhookWindowsHookEx(hKeyboardHook);
                hKeyboardHook = 0;
            }
        }
        private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
        {
            if ((nCode >= 0) && (OnKeyDownEvent != null || OnKeyUpEvent != null || OnKeyPressEvent != null))
            {
                KeyboardHookStruct MyKeyboardHookStruct = (KeyboardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyboardHookStruct));
                if (OnKeyPressEvent != null && (wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN))
                {
                    r1.AppendText("KeyCode:" + MyKeyboardHookStruct.vkCode + "| Time:" + DateTime.Now + "\r");
                }
            }
            return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);
        }
        private void KeyBordHook_OnKeyPressEvent(object sender, KeyPressEventArgs e) { }
    }

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            KeyRecord kr = new KeyRecord();
            kr.r1.Location = new Point(10, 10);
            this.Controls.Add(kr.r1);
            kr.Start();
        }
    }
}

[ITFU]

也可以试试keyup

[良朋]

用KeyDown判断KeyCode

if (e.KeyCode== Keys.CapsLock)
            {
             
            }

[asq985]

e.KeyValue

[Aspirant_Happy]

引用 1 楼 良朋的回复:

用KeyDown判断KeyCode

if (e.KeyCode== Keys.CapsLock)
            {
             
            }

刚刚试了一下，KeyDown可以，为什么KeyPress不行，好奇怪