制作实体类封闭的变化实体类

由网友(萝妹)分享简介：我有一个数据库的关系如下图所示。基于LINQ to SQL的ORM创建的域对象。一个支付包括现金支付和礼券付款。假设购买的总量为550可以支付如下组分1礼券值3001礼券值200我的现金货币值50我插入使用ORM的InsertOnSubmit功能的新的缴费记录。下面code是工作的罚款。不过，如果我的公司正在使用的信...

我有一个数据库的关系如下图所示。基于LINQ to SQL的ORM创建的域对象。

一个支付包括现金支付和礼券付款。假设购买的总量为550可以支付如下组分

  1礼券值300

1礼券值200

我的现金货币值50

我插入使用ORM的InsertOnSubmit功能的新的缴费记录。下面code是工作的罚款。不过，如果我的公司正在使用的信用卡引入一个新的支付部分，我需要改变我的支付领域类。我如何支付类打开的扩展和关闭更改还在使用的 ORM

注：支付类有行为（例如GetTotalAmountCollected）。我试图使支付类，以满足OCP。

注：有一个特定的的行为作为优惠券类型。是发出日期的优惠券是小于1/1/2000，它不应该在为总量（即，CouponValue应为零）计算中使用。请参阅Refactoring使用策略模式code 也。

注：我使用的的.Net 4.0

参考：

Getting在使用ObjectContext.AddObject与实体框架错误 Refactoring使用策略模式code preFER组成了继承？ EF 4.1 code-第一与模型/数据库一 Strategy模式和使用Unity 依赖注入 C# Strategy设计模式所代表VS OOP 如何使用策略模式用C＃？在继承与EF code第一：第2部分 - 每个类型表（TPT） http://weblogs.asp.net/manavi/archive/2010/12/28/inheritance-mapping-strategies-with-entity-framework-$c$c-first-ctp5-part-2-table-per-type-tpt.aspx

C＃code：

 公共类PaymentAppService
{
    公共RepositoryLayer.ILijosPaymentRepository库{获得;组; }

    公共无效MakePayment（）
    {
        DBML_Project.Payment paymentEntity =新DBML_Project.Payment（）;
        paymentEntity.PaymentID = 1;
        paymentEntity.PaymentType =PurchaseP;

        DBML_Project.CashPayment cashObj =新DBML_Project.CashPayment（）;
        cashObj.CashPaymentID = 1;
        cashObj.CurrencyNumber = 123;
        cashObj.CurrencyValue = 100;

        DBML_Project.GiftCouponPayment giftCouponObj =新DBML_Project.GiftCouponPayment（）;
        giftCouponObj.GiftCouponPaymentID = 1;
        giftCouponObj.CouponValue = 200;
        giftCouponObj.CouponNumber = 124;

        paymentEntity.CashPayments =新System.Data.Linq.EntitySet＆LT; DBML_Project.CashPayment＆GT;（）;
        paymentEntity.CashPayments.Add（cashObj）;

        paymentEntity.GiftCouponPayments =新System.Data.Linq.EntitySet＆LT; DBML_Project.GiftCouponPayment＆GT;（）;
        paymentEntity.GiftCouponPayments.Add（giftCouponObj）;

        Repository.InsertEntity（paymentEntity）;
        Repository.SubmitChanges（）;
    }
}

存储库：

 公共类LijosPaymentRepository：ILijosPaymentRepository
{
    公共System.Data.Linq.DataContext MyDataContext {获得;组; }

    公共无效InsertEntity（DBML_Project.Payment付款）
    {
        //将实体
        MyDataContext.GetTable＆LT; DBML_Project.Payment＆GT;（）InsertOnSubmit（付款）。
    }

    公共无效的SubmitChanges（）
    {
        MyDataContext.SubmitChanges（）;
    }
}

解决方案

对于@Lijo试图解决抽象的方法会更好的问题的

我想你可以实现你自己的IPayment接口，可通过整个应用程序中使用的CashPayment类型进行部分类。然后该接口也可对类：CreditCardPayment：

例如：

 

公共接口IPayment
{
     INT标识{获取;组; }
     INT PaymentId {获得;组; }
     //其他支付特定属性或方法
}

公共部分类CashPayment：IPayment
{
    公众诠释标识
    {
       {返回CashPaymentId; }
       集合{CashPaymentId =价值; }
    }

    //其它性能

}

公共部分类类：CreditCardPayment：IPayment
{
   //更多code ...
}

东西在你的EF方面得到的所有款项

 


公共部分类PaymentEntities //你的EF实体的名称
{
   公开IQueryable的AllPayments
   {
      返回this.CashPayment.Union（this.CreditCardPayment）; //这是不好的，但只是一个例子。抽象类的办法是更好地在这里。
   }

    公共无效InsertPayment（IPayment付款）
    {
         this.AddObject（payment.GetType（）名称，付款。）;
    }
}

I have a database relationship as shown below. The domain objects are created based on LINQ to SQL ORM.

A payment comprises of Cash Payment and Gift Coupon Payments. Suppose the total amount of purchase is 550. It can be paid as following components

1 Gift Coupon Valued 300

1 Gift Coupon Valued 200

I Cash Currency Valued 50

I am inserting new payment records using the "InsertOnSubmit" function of ORM. The following code is working fine. However, if I the company is introducing a new payment component using credit card, I need to make changes to my "Payment" domain class. How do I make the payment class Open for Extension and Closed for Changes still using ORM?

Note: The Payment class has behaviors (E.g. GetTotalAmountCollected). I am trying to make the "Payment" class to satisfy OCP.

Note: There is a specific behavior for Coupon type. Is the Coupon issued date is less than 1/1/2000, it should not be used in calculation for Total Amount (i.e, CouponValue should be zero). Refer Refactoring code using Strategy Pattern also.

Note: I am using .Net 4.0

Reference:

Getting an error when using ObjectContext.AddObject with Entity Framework Refactoring code using Strategy Pattern Prefer composition over inheritance? EF 4.1 Code-first vs Model/Database-first Strategy Pattern and Dependency Injection using Unity C# Strategy Design Pattern by Delegate vs OOP How to use the Strategy Pattern with C#? Inheritance with EF Code First: Part 2 – Table per Type (TPT) http://weblogs.asp.net/manavi/archive/2010/12/28/inheritance-mapping-strategies-with-entity-framework-code-first-ctp5-part-2-table-per-type-tpt.aspx

C# Code:

public class PaymentAppService
{
    public RepositoryLayer.ILijosPaymentRepository Repository { get; set; }

    public void MakePayment()
    {
        DBML_Project.Payment paymentEntity = new DBML_Project.Payment();
        paymentEntity.PaymentID = 1;
        paymentEntity.PaymentType = "PurchaseP";

        DBML_Project.CashPayment cashObj = new DBML_Project.CashPayment();
        cashObj.CashPaymentID = 1;
        cashObj.CurrencyNumber = 123;
        cashObj.CurrencyValue = 100;

        DBML_Project.GiftCouponPayment giftCouponObj = new DBML_Project.GiftCouponPayment();
        giftCouponObj.GiftCouponPaymentID = 1;
        giftCouponObj.CouponValue = 200;
        giftCouponObj.CouponNumber = 124;

        paymentEntity.CashPayments = new System.Data.Linq.EntitySet<DBML_Project.CashPayment>();
        paymentEntity.CashPayments.Add(cashObj);

        paymentEntity.GiftCouponPayments = new System.Data.Linq.EntitySet<DBML_Project.GiftCouponPayment>();
        paymentEntity.GiftCouponPayments.Add(giftCouponObj);

        Repository.InsertEntity(paymentEntity);
        Repository.SubmitChanges();
    }
}

Repository:

public class LijosPaymentRepository : ILijosPaymentRepository
{
    public System.Data.Linq.DataContext MyDataContext { get; set; }

    public void InsertEntity(DBML_Project.Payment payment)
    {
        //Insert the entity
        MyDataContext.GetTable<DBML_Project.Payment>().InsertOnSubmit(payment);
    }

    public void SubmitChanges()
    {
        MyDataContext.SubmitChanges();
    }
}

解决方案

For the problem that @Lijo tries to solve the abstract approach would be better

I think you can make a partial class on the CashPayment type that implements your own IPayment interface, which can be used through the whole application. This interface can then also be on CreditCardPayment:

Example:



public interface IPayment
{
     int Id { get; set; }
     int PaymentId { get; set; }
     //Other payment specific properties or methods
}

public partial class CashPayment : IPayment
{
    public int Id 
    {
       get { return CashPaymentId ; }
       set { CashPaymentId = value; }
    }

    //Other properties

}

public partial class CreditCardPayment : IPayment 
{
   //more code ...
}

Something on your EF context to get all payments




public partial class PaymentEntities //The name of your EF entities
{
   public IQueryable AllPayments
   {
      return this.CashPayment.Union(this.CreditCardPayment); //This is not good, but just an example. The abstract class approach would be better here.
   }

    public void InsertPayment(IPayment payment)
    {
         this.AddObject(payment.GetType().Name, payment);
    }
}

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相关专题：实体类；发布时间：2023-09-02 10:17:09