[代码]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;



interface



uses

  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 ms

end;



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。

Technorati 标签: Delphi, Hook, CTRL