如何设置IB的组合合约

You need to set AltSymbol of the instrument using following format:

设置AltSymbol为如下格式

Symbol;Leg1;Leg2;...;LegN 
where Leg is
ConId_Ratio_Action_Exchange_OpenClose_ShortSaleSlot_DesignatedLocation

for example

例如

IBM;78491274_1_SELL_SMART_0_0_;81524101_1_BUY_SMART_0_0