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改键是一种习惯，比如在玩儿lol或者dota的时候。理论上玩儿什么游戏都可以改键。

做一个窗体（点击Install——应用改键，点击Uninstall——撤销应用）：

窗体定义代码如下：

using System.Windows.Forms;namespace KeysExchange{    partial class Form1    {        /// 
        /// Required designer variable.        /// 
        private System.ComponentModel.IContainer components = null;        /// 
        /// Clean up any resources being used.        /// 
        /// true if managed resources should be disposed; otherwise, false.        protected override void Dispose(bool disposing)        {            if (disposing && (components != null))            {                components.Dispose();            }            base.Dispose(disposing);        }        #region Windows Form Designer generated code        /// 
        /// Required method for Designer support - do not modify        /// the contents of this method with the code editor.        /// 
        private void InitializeComponent()        {            this.intall_button = new System.Windows.Forms.Button();            this.uninstall_button = new System.Windows.Forms.Button();            this.comboBox1 = new System.Windows.Forms.ComboBox();            this.comboBox2 = new System.Windows.Forms.ComboBox();            this.label1 = new System.Windows.Forms.Label();            this.SuspendLayout();            //             // intall_button            //             this.intall_button.Location = new System.Drawing.Point(179, 162);            this.intall_button.Name = "intall_button";            this.intall_button.Size = new System.Drawing.Size(75, 23);            this.intall_button.TabIndex = 4;            this.intall_button.Text = "Install";            this.intall_button.UseVisualStyleBackColor = true;            this.intall_button.Click += new System.EventHandler(this.intall_button_Click);            //             // uninstall_button            //             this.uninstall_button.Location = new System.Drawing.Point(179, 207);            this.uninstall_button.Name = "uninstall_button";            this.uninstall_button.Size = new System.Drawing.Size(75, 23);            this.uninstall_button.TabIndex = 5;            this.uninstall_button.Text = "Uninstall";            this.uninstall_button.UseVisualStyleBackColor = true;            this.uninstall_button.Click += new System.EventHandler(this.uninstall_button_Click);            //             // comboBox1            //             this.comboBox1.FormattingEnabled = true;            this.comboBox1.Location = new System.Drawing.Point(54, 41);            this.comboBox1.Name = "comboBox1";            this.comboBox1.Size = new System.Drawing.Size(57, 21);            this.comboBox1.TabIndex = 6;            this.comboBox1.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;            //             // comboBox2            //             this.comboBox2.FormattingEnabled = true;            this.comboBox2.Location = new System.Drawing.Point(175, 41);            this.comboBox2.Name = "comboBox2";            this.comboBox2.Size = new System.Drawing.Size(57, 21);            this.comboBox2.TabIndex = 7;            this.comboBox2.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;            //             // label1            //             this.label1.AutoSize = true;            this.label1.Location = new System.Drawing.Point(126, 44);            this.label1.Name = "label1";            this.label1.Size = new System.Drawing.Size(43, 13);            this.label1.TabIndex = 8;            this.label1.Text = "改为：";            //             // Form1            //             this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;            this.ClientSize = new System.Drawing.Size(301, 273);            this.Controls.Add(this.label1);            this.Controls.Add(this.comboBox2);            this.Controls.Add(this.comboBox1);            this.Controls.Add(this.uninstall_button);            this.Controls.Add(this.intall_button);            this.Name = "Form1";            this.Text = "KeysExchange";            this.ResumeLayout(false);            this.PerformLayout();        }        #endregion        private System.Windows.Forms.Button intall_button;        private System.Windows.Forms.Button uninstall_button;        private System.Windows.Forms.ComboBox comboBox1;        private System.Windows.Forms.ComboBox comboBox2;        private System.Windows.Forms.Label label1;    }    struct ComboItem    {        private string text;        private string value;        public ComboItem(string text, string value)        {            this.text = text;            this.value = value;        }        public override string ToString()        {            return this.text;        }        public string ToValue()        {            return this.value;        }    }}

钩子代码如下：

using System;using System.Diagnostics;using System.Runtime.InteropServices;namespace KeysExchange{    public class KeyboardHookLib    {        private const int WH_KEYBOARD_LL = 13;              private delegate int HookHandle(int nCode, int wParam, IntPtr lParam);        public delegate void ProcessKeyHandle(HookStruct param, out bool handle);        private static int _hHookValue = 0;        private HookHandle _KeyBoardHookProcedure;        [StructLayout(LayoutKind.Sequential)]        public class HookStruct        {            public int vkCode;            public int scanCode;            public int flags;            public int time;            public int dwExtraInfo;        }        [DllImport("user32.dll")]        private static extern int SetWindowsHookEx(int idHook, HookHandle lpfn, IntPtr hInstance, int threadId);        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]        private static extern bool UnhookWindowsHookEx(int idHook);        [DllImport("user32.dll")]        private static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);        [DllImport("kernel32.dll")]        private static extern int GetCurrentThreadId();        [DllImport("kernel32.dll")]        private static extern IntPtr GetModuleHandle(string name);        private IntPtr _hookWindowPtr = IntPtr.Zero;        public KeyboardHookLib() { }        private static ProcessKeyHandle _clientMethod = null;        [DllImport("user32")]        public static extern int GetKeyboardState(byte[] pbKeyState);        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]        private static extern short GetKeyState(int vKey);        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        public void InstallHook(ProcessKeyHandle clientMethod)        {            _clientMethod = clientMethod;            if (_hHookValue == 0)            {                _KeyBoardHookProcedure = new HookHandle(OnHookProc);                _hookWindowPtr = GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName);                _hHookValue = SetWindowsHookEx(WH_KEYBOARD_LL, _KeyBoardHookProcedure, _hookWindowPtr, 0);                if (_hHookValue == 0) UninstallHook();            }        }        public void UninstallHook()        {            if (_hHookValue != 0)            {                if (UnhookWindowsHookEx(_hHookValue))                {                    _hHookValue = 0;                }            }        }        private static int OnHookProc(int nCode, int wParam, IntPtr lParam)        {            if (nCode >= 0)            {                HookStruct hookStruct = (HookStruct)Marshal.PtrToStructure(lParam, typeof(HookStruct));                if (_clientMethod != null)                {                    bool handle = false;                    ///Tylan: Judge if the event is KeyDown or not.                    if (lParam.ToInt32() > 0 && wParam == 0x100)                    {                        _clientMethod(hookStruct, out handle);                    }                    if (handle) return 1;                 }            }            return CallNextHookEx(_hHookValue, nCode, wParam, lParam);        }    }}

逻辑部分代码如下：

using System;using System.Windows.Forms;namespace KeysExchange{    public partial class Form1 : Form    {        private KeyboardHookLib _keyboardHook = null;        public Form1()        {            InitializeComponent();            for (int alp = 65; alp <= 90; alp++)            {                ComboItem item = new ComboItem(((Keys)alp).ToString(), alp.ToString());                comboBox1.Items.Add(item);                comboBox2.Items.Add(item);            }        }        private void intall_button_Click(object sender, EventArgs e)        {            //Install the hook.            _keyboardHook = new KeyboardHookLib();            _keyboardHook.InstallHook(this.OnKeyPress);        }        private void uninstall_button_Click(object sender, EventArgs e)        {            //Cancel the hook.            if (_keyboardHook != null) _keyboardHook.UninstallHook();        }        public void OnKeyPress(KeyboardHookLib.HookStruct hookStruct, out bool handle)        {            handle = false;            if (((Keys)hookStruct.vkCode).ToString() == comboBox1.SelectedItem.ToString())             {                handle = true;                //Exchange the keys.                hookStruct.vkCode = int.Parse(((ComboItem)comboBox2.SelectedItem).ToValue());                Keys key = (Keys)hookStruct.vkCode;                //MessageBox.Show((key == Keys.None ? "" : key.ToString()));                System.Windows.Forms.SendKeys.Send(key.ToString().ToLower());            }        }    }}

F5运行，找个游戏试一下，改键成功啦（按p成功打开背包）~