delphi - 如何处理数据库应用程序的 sleep 模式网络丢失

Question

我有几个 Delphi 程序维护与数据库的连接(一些是 Oracle，一些是 Firebird)。如果程序在 Windows 进入休眠模式时运行，则与数据库的连接就会丢失。处理这种情况的最佳方法是什么？有没有办法在网络进入休眠模式之前接收事件，以便我可以尝试更好地处理这种情况？

Answer 1

要详细说明 RRUZ，您需要类似以下内容:

procedure WMPowerBroadcast(var AMessage: TMessage); message WM_POWERBROADCAST;

以您的形式。那么 WMPowerBroadcast 将类似于:

procedure TMyForm.WMPowerBroadcast(var AMessage: TMessage);
const
  PBT_APMSUSPEND = 4;
  PBT_APMRESUMESUSPEND = 7;
begin
  case AMessage.WParam of
    PBT_APMSUSPEND:
    begin
      // save your DB stuff. NOTE: IIRC you are pretty limited in the time 
      // you get to do this - 2 seconds ? may be the limit
    end;
    PBT_APMRESUMESUSPEND:
    begin
      // restore your DB connection
    end;
  else
     // you're going to want to handle PBT_APMRESUMECRITICAL (XP and older systems) and PBT_APMRESUMEAUTOMATIC differently
     // IIRC you did not get notification of the suspend in this case
  end;
end;