factory.function不是angularjs中的函数

我想删除购物车中的项目。为此，我对单个项使用函数canceldummy（）。这里我的问题是，删除时我得到了一个错误

NewOrderFactory.deleteDummyOrder is not a function
at deleteDummy (TiffinServices.js:55)
at Scope.$scope.canceldummy (TiffinControllers.js:357)
at fn (eval at <anonymous> (angular.js:13365), <anonymous>:4:651)
at callback (angular.js:23613)
at Scope.$eval (angular.js:16052)
at Scope.$apply (angular.js:16152)
at HTMLAnchorElement.<anonymous> (angular.js:23618)
at HTMLAnchorElement.n.event.dispatch (jquery-2.2.0.min.js:3)
at HTMLAnchorElement.r.handle (jquery-2.2.0.min.js:3)

这是我的服务代码

servctrl.service("NewOrderService",function(NewOrderFactory){                                                 
    this.deleteDummy=function(idx){ 
        NewOrderFactory.deleteDummyOrder(idx);
    }
})

这是我的工厂代码

factmodule.factory("NewOrderFactory",function(){
    var OrderItemList={Items:[]}
    return{
        deleteDummyOrder: function(idx){
            OrderItemList.Items.splice(idx,1);
        }
    }
})

---

如何删除此错误？

我认为错误在工厂中，请在工厂中尝试以下代码：

factmodule.factory("NewOrderFactory",function(){

  var OrderItemList={Items:[]};
  OrderItemList.deleteDummyOrder: function(idx){
      OrderItemList.Items.splice(idx,1);      
  }
  return OrderItemList;
})

factmodule.factory("NewOrderFactory",function(){
    var OrderItemList={Items:[]}
    return{
        deleteDummyOrder: function(idx){
            OrderItemList.Items.splice(idx,1);
        }
    }
})

factmodule.factory("NewOrderFactory",function(){

  var OrderItemList={Items:[]};
  OrderItemList.deleteDummyOrder: function(idx){
      OrderItemList.Items.splice(idx,1);      
  }
  return OrderItemList;
})