技术文档MQL5参考标准程序库策略模块智能交易基准类CExpertTradeEventOrderPlacedTradeEventOrderPlacedTradeEventOrderPlaced“放置挂单” 事件处理器。virtual bool TradeEventOrderPlaced()返回值 类 CExpert 方法不做任何事且永远返回 true。TradeEventPositionClosedTradeEventOrderModified