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unit SystemCriticalU;
interface
uses
Windows;
type
TSystemCritical = class
private
FIsCritical: Boolean;
procedure SetIsCritical(const Value: Boolean) ;
protected
procedure UpdateCritical(Value: Boolean) ; virtual;
public
constructor Create;
property IsCritical: Boolean read FIsCritical write SetIsCritical;
end;
var
SystemCritical: TSystemCritical;
implementation
{ TSystemCritical }
// REF: http://msdn.microsoft.com/en-us/library/aa373208.aspx
type
EXECUTION_STATE = DWORD;
const
ES_SYSTEM_REQUIRED = $00000001;
ES_DISPLAY_REQUIRED = $00000002;
ES_USER_PRESENT = $00000004;
ES_AWAYMODE_REQUIRED = $00000040;
ES_CONTINUOUS = $80000000;
KernelDLL = 'kernel32.dll';
{
SetThreadExecutionState Function
Enables an application to inform the system that it is in use,
thereby preventing the system from entering sleep or turning off the
display while the application is running.
}
procedure SetThreadExecutionState(ESFlags: EXECUTION_STATE);
stdcall; external kernel32 name 'SetThreadExecutionState';
constructor TSystemCritical.Create;
begin
inherited;
FIsCritical := False;
end;
procedure TSystemCritical.SetIsCritical(const Value: Boolean) ;
begin
if FIsCritical = Value then
Exit;
FIsCritical := Value;
UpdateCritical(FIsCritical);
end;
procedure TSystemCritical.UpdateCritical(Value: Boolean) ;
begin
if Value then
// 防止睡眠空閑超時和關(guān)機(jī)。
SetThreadExecutionState(ES_SYSTEM_REQUIRED or ES_CONTINUOUS)
else
//清除執(zhí)行狀態(tài)標(biāo)志以禁用離開模式并允許
// 系統(tǒng)空閑以正常睡眠
SetThreadExecutionState(ES_CONTINUOUS);
end;
initialization
SystemCritical := TSystemCritical.Create;
finalization
SystemCritical.IsCritical := False;
SystemCritical.Free;
end.
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