Delphi实现双击左CTRL键调用记事本

要实现对双击左CTRL键的监控，必须玩钩子了。

代码很简单，新建VCL Form的工程，在窗体上放两个按钮，分别叫做 btnHook 和 btnUnHook。

调用就是 BeginHook 和 EndHook 这两个函数，窗体代码如下：

unit frmTestHookWinKey;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls, ShellAPI;type  TForm1 = class(TForm)    btnHook: TButton;    btnUnHook: TButton;    procedure btnHookClick(Sender: TObject);    procedure btnUnHookClick(Sender: TObject);    procedure FormCreate(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;var  Form1: TForm1;implementation{$R *.dfm}var  KeyHook: HHook;  HitTime: Cardinal;                                    // 击键的间隔时间  HitThreshold: Integer;                                // 击键的间隔时间门限function HookKey(Code: integer; wParam: wParam; lParam: lParam): LRESULT; stdcall;type  PKBDLLHOOKSTRUCT = ^KBDLLHOOKSTRUCT;  KBDLLHOOKSTRUCT = record    vkCode: DWORD;    ScanCode: DWORD;    Flags: DWORD;    Time: DWORD;    dwExtraInfo: DWORD;  end;begin  // 如果左 CTRL 键按下  if (Code = HC_ACTION) and (PKBDLLHOOKSTRUCT(lParam).vkCode = VK_LCONTROL) and (wParam = WM_KEYDOWN) then begin    if HitTime > 0 then begin      HitTime := GetTickCount - HitTime;                // 取得间隔时间      if HitTime <= HitThreshold then begin      // 如果间隔时间在门限时间之内，则调用记事本        WinExec('notepad.exe', SW_SHOWNORMAL);        HitTime := 0;      end      else        HitTime := GetTickCount;    end    else      HitTime := GetTickCount;  end;  Result := CallNextHookEx(KeyHook, Code, wParam, lParam);end;procedure BeginHook;begin  KeyHook := SetWindowsHookEx(13 {=WH_KEYBOARD_LL}, @HookKey, HInstance, 0);end;procedure EndHook;begin  UnhookWindowsHookEx(KeyHook);end;procedure TForm1.btnHookClick(Sender: TObject);begin  BeginHook;end;procedure TForm1.btnUnHookClick(Sender: TObject);begin  EndHook;end;procedure TForm1.FormCreate(Sender: TObject);begin  HitTime := 0;  HitThreshold := 200;                                  // 200 msend;end.

既然调用记事本都搞定了，干些其他的事儿自然不在话下了。

这段代码完全可以封装为一个模块，将监控的按键、间隔时间及回调函数当作参数传入即可。