Delphi编写的一款锁屏小工具,双击程序立即锁屏，木有界面的。解除锁屏密码：alt+空格。

unit Unit1;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, ExtCtrls;

type

  TForm1 = class(TForm)

    Image1: TImage;

    Timer2: TTimer;

    procedure FormCreate(Sender: TObject);

    procedure Timer2Timer(Sender: TObject);

    procedure HotKeyDown(var Msg: Tmessage); message WM_HOTKEY;

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

  FullScreen : Tbitmap;

  FullScreenCanvas : TCanvas;

  DC : HDC;

  HotKeyId: Integer;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);

begin

  HotKeyId := GlobalAddAtom('MyHotKey') - $C000;

  RegisterHotKey(Handle, hotkeyid, MOD_ALT, VK_SPACE);

  FullScreen := Tbitmap.Create;

  FullScreen.Width := screen.Width;

  FullScreen.Height := Screen.Height;

  DC := GetDC(0);

  FullScreenCanvas := TCanvas.Create;

  FullScreenCanvas.Handle := DC;

  FullScreen.Canvas.CopyRect(Rect(0, 0, Screen.Width, Screen.Height), FullScreenCanvas, Rect(0, 0, Screen.Width, Screen.Height));

  FullScreenCanvas.Free;

  ReleaseDC(0, DC);

  Image1.Picture.Bitmap := FullScreen;

  image1.Width := FullScreen.Width;

  Image1.Height := FullScreen.Height;

  FullScreen.Free;

  //*****************************************

  Form1.Left := 0;

  Form1.Top := 0;

  Form1.Width := Screen.Width;

  Form1.Height := Screen.Height;

  Image1.Left := 0;

  Image1.Top := 0;

end;

procedure TForm1.Timer2Timer(Sender: TObject);

begin

 SetWindowPos(handle, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE + SWP_NOMOVE);  //当前窗口置顶

end;

procedure TForm1.HotKeyDown(var Msg: Tmessage);

begin 

if (Msg.LparamLo = MOD_ALT) AND (Msg.LParamHi = VK_SPACE) then // 热键为ALT+空格

begin

    Application.Terminate;              //窗口结束

     UnRegisterHotKey(handle, HotKeyId); //释放热键资源

end;

end;

end.