How to detect when the laptop is running on batteries? - delphi

Question

How to detect (from Delphi) when the laptop is running on batteries (or AC)?

Answer 1

To be notified when the status changes on Vista and Windows 7 you can use RegisterPowerSettingNotification.
For Windows 2000 and later, look at GetSystemPowerStatus, or go to MSDN and read about Power Management.
(Someone always posts while I am typing :-( )
function GetBattery : Boolean;
var
SysPowerStatus: TSystemPowerStatus;
begin
Win32Check(GetSystemPowerStatus(SysPowerStatus));
case SysPowerStatus.ACLineStatus of
0: Result := False;
1: begin
Result := True;
// You can return life with
// String := Format('Battery power left: %u percent.', SysPowerStatus.BatteryLifePercent]);
end;
else
raise Exception.Create('Unknown battery status');
end;
end;

Answer 2

There's a WINAPI function that I believe does this, GetSystemPowerStatus, which I believe you can execute from Delphi.

Answer 3

Here part of code that detect when laptop is running on batteries (if not it triggers some event):
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
WTSSessionNotification, StdCtrls, MediaPlayer, Buttons, ShellAPI, Settings,
ExtCtrls;
const
WM_ICONTRAY = WM_USER + 1;
type
TSettingsForm = class(TForm)
OpenDialog: TOpenDialog;
pnl1: TPanel;
InfoLabel: TLabel;
grp1: TGroupBox;
AlarmSoundLabel: TLabel;
lbl1: TLabel;
checkIfLocked: TCheckBox;
Filename: TEdit;
Browse: TBitBtn;
TestSound: TBitBtn;
btn1: TBitBtn;
lbl2: TLabel;
procedure Minimize(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure TestSoundClick(Sender: TObject);
procedure BrowseClick(Sender: TObject);
procedure checkIfLockedClick(Sender: TObject);
procedure OpenHomepage(Sender: TObject);
procedure btn1Click(Sender: TObject);
private
TrayIconData: TNotifyIconData;
procedure CheckForAC;
protected
procedure WndProc(var Message: TMessage); override;
public
{ Public declarations }
Function SecuredLockWorkStation : Boolean ;
end;
var
SettingsForm: TSettingsForm;
implementation
{$R *.DFM}
{$R WindowsXP.RES}
var
MPlayer: TMPlayer;
mySettings: TSettings;
isLocked: boolean = false;
// true if A/C is connected, false if not
function ACConnected: boolean;
var PowerStatus: TSystemPowerStatus;
begin
GetSystemPowerStatus(PowerStatus);
result := (PowerStatus.ACLineStatus = 1);
end;
// handles application.minimize; do not really
// minimize, but hide settings window
procedure TSettingsForm.Minimize(Sender: TObject);
begin
Application.Restore;
self.Hide;
end;
// processes window messages (notification about
// power status changes, locking of workstation and
// tray icon activity)
procedure TSettingsForm.WndProc(var Message: TMessage);
begin
case Message.Msg of
WM_WTSSESSION_CHANGE:
begin
if Message.wParam = WTS_SESSION_LOCK then
isLocked := true;
if Message.wParam = WTS_SESSION_UNLOCK then
begin
isLocked := false;
if MPlayer.isPlaying then
MPlayer.Close;
end;
end;
WM_POWERBROADCAST:
begin
if (isLocked) or (checkIfLocked.checked=false) then
CheckForAC;
end;
WM_ICONTRAY:
begin
case Message.lParam of
WM_LBUTTONDOWN:
begin
if SettingsForm.visible then
SettingsForm.Hide
else
SettingsForm.Show;
end;
WM_RBUTTONUP:
begin
if SettingsForm.visible then
SettingsForm.Hide
else
SettingsForm.Close;
end;
end;
end;
end;
inherited;
end;