My form's init method look that:
public void init()
{
ConFMSVehicleTable callerVehicle;
super();
switch(element.args().dataset())
{
case tableNum(ConFMSVehicleTable):
callerVehicle =element.args().record();
break;
}
if(callerVehicle.RecId == 0)
{
throw error("@SYS79604");
}
contract = ConFMSVehicleGroupChangeContract::construct();
contract.vehicleId(callerVehicle.VehicleId);
contract.vehicleGroupId(callerVehicle.VehicleGroupId);
}