表单在后台时如何读取键盘输入c#

时间:2017-04-07 08:23:59

标签: c#

我需要能够在我的表单在后台(不一定隐藏)时读取键盘输入。这里有类似的问题,但我需要确定是否按下了女巫键,我需要得到它的价值,因为" Key"不是int(像0x00357这样的东西,我不知道那是什么)。具体来说,我需要检查当前是否按下了用户确定的按键。我怎么能这样做?

1 个答案:

答案 0 :(得分:1)

比您要求的晚了几年,但这是我在创建可监听按键的应用程序时使用的方法,并且预定义列表中的任何内容都将镜像到其他后台进程以在游戏中启用多重装箱。

Ciantic's Github上有一个很棒的键盘监听器,如果链接无效,那么这里的代码-

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;
using System.Windows.Input;
using System.Windows.Threading;
using System.Collections.Generic;

namespace Ownskit.Utils
{
    /// <summary>
    /// Listens keyboard globally.
    /// 
    /// <remarks>Uses WH_KEYBOARD_LL.</remarks>
    /// </summary>
    public class KeyboardListener : IDisposable
    {
        /// <summary>
        /// Creates global keyboard listener.
        /// </summary>
        public KeyboardListener()
        {
            // Dispatcher thread handling the KeyDown/KeyUp events.
            this.dispatcher = Dispatcher.CurrentDispatcher;

            // We have to store the LowLevelKeyboardProc, so that it is not garbage collected runtime
            hookedLowLevelKeyboardProc = (InterceptKeys.LowLevelKeyboardProc)LowLevelKeyboardProc;

            // Set the hook
            hookId = InterceptKeys.SetHook(hookedLowLevelKeyboardProc);

            // Assign the asynchronous callback event
            hookedKeyboardCallbackAsync = new KeyboardCallbackAsync(KeyboardListener_KeyboardCallbackAsync);
        }

        private Dispatcher dispatcher;

        /// <summary>
        /// Destroys global keyboard listener.
        /// </summary>
        ~KeyboardListener()
        {
            Dispose();
        }

        /// <summary>
        /// Fired when any of the keys is pressed down.
        /// </summary>
        public event RawKeyEventHandler KeyDown;

        /// <summary>
        /// Fired when any of the keys is released.
        /// </summary>
        public event RawKeyEventHandler KeyUp;

        #region Inner workings

        /// <summary>
        /// Hook ID
        /// </summary>
        private IntPtr hookId = IntPtr.Zero;

        /// <summary>
        /// Asynchronous callback hook.
        /// </summary>
        /// <param name="character">Character</param>
        /// <param name="keyEvent">Keyboard event</param>
        /// <param name="vkCode">VKCode</param>
        private delegate void KeyboardCallbackAsync(InterceptKeys.KeyEvent keyEvent, int vkCode, string character);

        /// <summary>
        /// Actual callback hook.
        /// 
        /// <remarks>Calls asynchronously the asyncCallback.</remarks>
        /// </summary>
        /// <param name="nCode"></param>
        /// <param name="wParam"></param>
        /// <param name="lParam"></param>
        /// <returns></returns>
        [MethodImpl(MethodImplOptions.NoInlining)]
        private IntPtr LowLevelKeyboardProc(int nCode, UIntPtr wParam, IntPtr lParam)
        {
            string chars = "";

            if (nCode >= 0)
                if (wParam.ToUInt32() == (int)InterceptKeys.KeyEvent.WM_KEYDOWN ||
                    wParam.ToUInt32() == (int)InterceptKeys.KeyEvent.WM_KEYUP ||
                    wParam.ToUInt32() == (int)InterceptKeys.KeyEvent.WM_SYSKEYDOWN ||
                    wParam.ToUInt32() == (int)InterceptKeys.KeyEvent.WM_SYSKEYUP)
                {
                    // Captures the character(s) pressed only on WM_KEYDOWN
                    chars = InterceptKeys.VKCodeToString((uint)Marshal.ReadInt32(lParam), 
                        (wParam.ToUInt32() == (int)InterceptKeys.KeyEvent.WM_KEYDOWN ||
                        wParam.ToUInt32() == (int)InterceptKeys.KeyEvent.WM_SYSKEYDOWN));

                    hookedKeyboardCallbackAsync.BeginInvoke((InterceptKeys.KeyEvent)wParam.ToUInt32(), Marshal.ReadInt32(lParam), chars, null, null);
                }

            return InterceptKeys.CallNextHookEx(hookId, nCode, wParam, lParam);
        }

        /// <summary>
        /// Event to be invoked asynchronously (BeginInvoke) each time key is pressed.
        /// </summary>
        private KeyboardCallbackAsync hookedKeyboardCallbackAsync;

        /// <summary>
        /// Contains the hooked callback in runtime.
        /// </summary>
        private InterceptKeys.LowLevelKeyboardProc hookedLowLevelKeyboardProc;

        /// <summary>
        /// HookCallbackAsync procedure that calls accordingly the KeyDown or KeyUp events.
        /// </summary>
        /// <param name="keyEvent">Keyboard event</param>
        /// <param name="vkCode">VKCode</param>
        /// <param name="character">Character as string.</param>
        void KeyboardListener_KeyboardCallbackAsync(InterceptKeys.KeyEvent keyEvent, int vkCode, string character)
        {
            switch (keyEvent)
            {
                // KeyDown events
                case InterceptKeys.KeyEvent.WM_KEYDOWN:
                    if (KeyDown != null)
                        dispatcher.BeginInvoke(new RawKeyEventHandler(KeyDown), this, new RawKeyEventArgs(vkCode, false, character));
                    break;
                case InterceptKeys.KeyEvent.WM_SYSKEYDOWN:
                    if (KeyDown != null)
                        dispatcher.BeginInvoke(new RawKeyEventHandler(KeyDown), this, new RawKeyEventArgs(vkCode, true, character));
                    break;

                // KeyUp events
                case InterceptKeys.KeyEvent.WM_KEYUP:
                    if (KeyUp != null)
                        dispatcher.BeginInvoke(new RawKeyEventHandler(KeyUp), this, new RawKeyEventArgs(vkCode, false, character));
                    break;
                case InterceptKeys.KeyEvent.WM_SYSKEYUP:
                    if (KeyUp != null)
                        dispatcher.BeginInvoke(new RawKeyEventHandler(KeyUp), this, new RawKeyEventArgs(vkCode, true, character));
                    break;

                default:
                    break;
            }
        }

        #endregion

        #region IDisposable Members

        /// <summary>
        /// Disposes the hook.
        /// <remarks>This call is required as it calls the UnhookWindowsHookEx.</remarks>
        /// </summary>
        public void Dispose()
        {
            InterceptKeys.UnhookWindowsHookEx(hookId);
        }

        #endregion
    }

    /// <summary>
    /// Raw KeyEvent arguments.
    /// </summary>
    public class RawKeyEventArgs : EventArgs
    {
        /// <summary>
        /// VKCode of the key.
        /// </summary>
        public int VKCode;

        /// <summary>
        /// WPF Key of the key.
        /// </summary>
        public Key Key;

        /// <summary>
        /// Is the hitted key system key.
        /// </summary>
        public bool IsSysKey;

        /// <summary>
        /// Convert to string.
        /// </summary>
        /// <returns>Returns string representation of this key, if not possible empty string is returned.</returns>
        public override string ToString()
        {
            return Character;
        }

        /// <summary>
        /// Unicode character of key pressed.
        /// </summary>
        public string Character;

        /// <summary>
        /// Create raw keyevent arguments.
        /// </summary>
        /// <param name="VKCode"></param>
        /// <param name="isSysKey"></param>
        /// <param name="Character">Character</param>
        public RawKeyEventArgs(int VKCode, bool isSysKey, string Character)
        {
            this.VKCode = VKCode;
            this.IsSysKey = isSysKey;
            this.Character = Character;
            this.Key = System.Windows.Input.KeyInterop.KeyFromVirtualKey(VKCode);
        }

    }

    /// <summary>
    /// Raw keyevent handler.
    /// </summary>
    /// <param name="sender">sender</param>
    /// <param name="args">raw keyevent arguments</param>
    public delegate void RawKeyEventHandler(object sender, RawKeyEventArgs args);

    #region WINAPI Helper class
    /// <summary>
    /// Winapi Key interception helper class.
    /// </summary>
    internal static class InterceptKeys
    {
        public delegate IntPtr LowLevelKeyboardProc(int nCode, UIntPtr wParam, IntPtr lParam);
        public static int WH_KEYBOARD_LL = 13;

        /// <summary>
        /// Key event
        /// </summary>
        public enum KeyEvent : int {    
            /// <summary>
            /// Key down
            /// </summary>
            WM_KEYDOWN = 256,

            /// <summary>
            /// Key up
            /// </summary>
            WM_KEYUP = 257,

            /// <summary>
            /// System key up
            /// </summary>
            WM_SYSKEYUP = 261,

            /// <summary>
            /// System key down
            /// </summary>
            WM_SYSKEYDOWN = 260
        }

        public static IntPtr SetHook(LowLevelKeyboardProc proc)
        {
            using (Process curProcess = Process.GetCurrentProcess())
            using (ProcessModule curModule = curProcess.MainModule)
            {
                return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
            }
        }

        [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, UIntPtr wParam, IntPtr lParam);

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

        #region Convert VKCode to string
        // Note: Sometimes single VKCode represents multiple chars, thus string. 
        // E.g. typing "^1" (notice that when pressing 1 the both characters appear, 
        // because of this behavior, "^" is called dead key)

        [DllImport("user32.dll")]
        private static extern int ToUnicodeEx(uint wVirtKey, uint wScanCode, byte[] lpKeyState, [Out, MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder pwszBuff, int cchBuff, uint wFlags, IntPtr dwhkl);

        [DllImport("user32.dll")]
        private static extern bool GetKeyboardState(byte[] lpKeyState);

        [DllImport("user32.dll")]
        private static extern uint MapVirtualKeyEx(uint uCode, uint uMapType, IntPtr dwhkl);

        [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
        private static extern IntPtr GetKeyboardLayout(uint dwLayout);

        [DllImport("User32.dll")]
        private static extern IntPtr GetForegroundWindow();

        [DllImport("User32.dll")]
        private static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);

        [DllImport("user32.dll")]
        private static extern bool AttachThreadInput(uint idAttach, uint idAttachTo, bool fAttach);

        [DllImport("kernel32.dll")]
        private static extern uint GetCurrentThreadId();

        private static uint lastVKCode = 0;
        private static uint lastScanCode = 0;
        private static byte[] lastKeyState = new byte[255];
        private static bool lastIsDead = false;

        /// <summary>
        /// Convert VKCode to Unicode.
        /// <remarks>isKeyDown is required for because of keyboard state inconsistencies!</remarks>
        /// </summary>
        /// <param name="VKCode">VKCode</param>
        /// <param name="isKeyDown">Is the key down event?</param>
        /// <returns>String representing single unicode character.</returns>
        public static string VKCodeToString(uint VKCode, bool isKeyDown)
        {
            // ToUnicodeEx needs StringBuilder, it populates that during execution.
            System.Text.StringBuilder sbString = new System.Text.StringBuilder(5);

            byte[] bKeyState = new byte[255];
            bool bKeyStateStatus;
            bool isDead = false;

            // Gets the current windows window handle, threadID, processID
            IntPtr currentHWnd = GetForegroundWindow();
            uint currentProcessID;
            uint currentWindowThreadID = GetWindowThreadProcessId(currentHWnd, out currentProcessID);

            // This programs Thread ID
            uint thisProgramThreadId = GetCurrentThreadId();

            // Attach to active thread so we can get that keyboard state
            if (AttachThreadInput(thisProgramThreadId, currentWindowThreadID , true))
            {
                // Current state of the modifiers in keyboard
                bKeyStateStatus = GetKeyboardState(bKeyState);

                // Detach
                AttachThreadInput(thisProgramThreadId, currentWindowThreadID, false);
            }
            else
            {
                // Could not attach, perhaps it is this process?
                bKeyStateStatus = GetKeyboardState(bKeyState);
            }

            // On failure we return empty string.
            if (!bKeyStateStatus)
                return "";

            // Gets the layout of keyboard
            IntPtr HKL = GetKeyboardLayout(currentWindowThreadID);

            // Maps the virtual keycode
            uint lScanCode = MapVirtualKeyEx(VKCode, 0, HKL);

            // Keyboard state goes inconsistent if this is not in place. In other words, we need to call above commands in UP events also.
            if (!isKeyDown)
                return "";

            // Converts the VKCode to unicode
            int relevantKeyCountInBuffer = ToUnicodeEx(VKCode, lScanCode, bKeyState, sbString, sbString.Capacity, (uint)0, HKL);

            string ret = "";

            switch (relevantKeyCountInBuffer)
            {
                // Dead keys (^,`...)
                case -1:
                    isDead = true;

                    // We must clear the buffer because ToUnicodeEx messed it up, see below.
                    ClearKeyboardBuffer(VKCode, lScanCode, HKL);
                    break;

                case 0:
                    break;

                // Single character in buffer
                case 1:
                    ret = sbString[0].ToString();
                    break;

                // Two or more (only two of them is relevant)
                case 2:
                default:
                    ret = sbString.ToString().Substring(0, 2);
                    break;
            }

            // We inject the last dead key back, since ToUnicodeEx removed it.
            // More about this peculiar behavior see e.g: 
            //   http://www.experts-exchange.com/Programming/System/Windows__Programming/Q_23453780.html
            //   http://blogs.msdn.com/michkap/archive/2005/01/19/355870.aspx
            //   http://blogs.msdn.com/michkap/archive/2007/10/27/5717859.aspx
            if (lastVKCode != 0 && lastIsDead)
            {
                System.Text.StringBuilder sbTemp = new System.Text.StringBuilder(5);
                ToUnicodeEx(lastVKCode, lastScanCode, lastKeyState, sbTemp, sbTemp.Capacity, (uint)0, HKL);
                lastVKCode = 0;

                return ret;
            }

            // Save these
            lastScanCode = lScanCode;
            lastVKCode = VKCode;
            lastIsDead = isDead;
            lastKeyState = (byte[])bKeyState.Clone();

            return ret;
        }

        private static void ClearKeyboardBuffer(uint vk, uint sc, IntPtr hkl)
        {
            System.Text.StringBuilder sb = new System.Text.StringBuilder(10);

            int rc;
            do {
                byte[] lpKeyStateNull = new Byte[255];
                rc = ToUnicodeEx(vk, sc, lpKeyStateNull, sb, sb.Capacity, 0, hkl);
            } while(rc < 0);
        }
        #endregion
    }
    #endregion
}

这是作者的用法-

在WPF中的用法:

App.xaml:
<Application ...
    Startup="Application_Startup"
    Exit="Application_Exit">
    ...

App.xaml.cs:

public partial class App : Application
{
    KeyboardListener KListener = new KeyboardListener();

    private void Application_Startup(object sender, StartupEventArgs e)
    {
        KListener.KeyDown += new RawKeyEventHandler(KListener_KeyDown);
    }

    void KListener_KeyDown(object sender, RawKeyEventArgs args)
    {
        Console.WriteLine(args.Key.ToString());
        Console.WriteLine(args.ToString()); // Prints the text of pressed button, takes in account big and small letters. E.g. "Shift+a" => "A"
    }

    private void Application_Exit(object sender, ExitEventArgs e)
    {
        KListener.Dispose();
    }
}

如果还需要侦听KeyUp事件,则也可以为其创建侦听器。生成的RawKeyEventArgs包含键名称,按下的字符和虚拟键代码。您可以使用其中任何一个与要响应的现有列表进行比较,并做出相应的反应。如果您需要验证按键的外观,则可以显示一个输入内容的消息框,并从中建立一个列表。

我希望这会有所帮助!