unitfrmmain.pas

《Delphi实用程序100例》配套书源码盘

unit unitFrmMain;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}
//打开屏幕保护程序
procedure TForm1.Button1Click(Sender: TObject);
begin
  SystemParametersInfo(SPI_SETSCREENSAVEACTIVE, 1, nil, 0);
end;
//关闭屏幕保护程序
procedure TForm1.Button2Click(Sender: TObject);
begin
  SystemParametersInfo(SPI_SETSCREENSAVEACTIVE, 0, nil, 0);
end;

function TurnScreenSaverOn: bool;
var
  TurnTag: bool;
begin
  result := false;
  if SystemParametersInfo(SPI_GETSCREENSAVEACTIVE, 0, @turntag, 0) <> true then exit;
  if not TurnTag then exit;
  PostMessage(GetDesktopWindow, WM_SYSCOMMAND, SC_SCREENSAVE, 0);
  result := true;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  TurnScreenSaverOn;
end;

end.