jcsqueryResult.First;
while not jcsdqryvehiclebydriverid.Eof do   //从TJsonClientDataSet中取出数据，存到ComboBox中
 begin
 v := Vehicle.Create();//这个类有vehicleno和id2个属性。
 v.vehicleno :=jcsqueryResult.FieldByName('vehicleno').AsString;
 v.id := jcsqueryResult.FieldByName('vehicleid').aslargeint; 
NovaVehicleNoComboBox.Items.AddObject(v.vehicleno, TObject(v));  //存到ComboBox中
jcsqueryResult.Next; 

end;

ve := (NovaVehicleNoComboBox.Items.Objects[NovaVehicleNoComboBox.ItemIndex] as  Vehicle);