将类的属性类型设计为接口类型

2009-10-27 06:16:35 276 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

MCGS 和 200SMART 时间同步在实际应用中，PLC经常会因为断电原因，导致时间不准确。假设我们设置了一个投加泵，每天8-18点投加。屏幕上显示的时间和PLC内部的时间，很可能不一样。所以需要在触摸屏上读取PLC的时间，并且提供设置功能。阅读详情

有这样一个场景:我做了一个小程序,需要对每天的开支情况进行登记.
我将开支类(Expense)设计如下:
public class Expense
{
private IAccount account;
private decimal amount;

public decimal Amount
{
get { return amount; }
set { amount = value; }
}

public IAccount Account
{
get { return account; }
set { account = value; }
}
public void Register()
{
account.Draw(amount);
}
}

这里Expense类中的Account属性我设计成了IAccount接口.原因是因为用于消费的帐户有很多种,比如CreditCard(信用卡)\Cash(现金)\DebitCard(借记卡)等等各种帐户:
public interface IAccount
{
string Name
{
get;
set;
}

decimal Amount
{
get;
set;
}

Individual Holder
{
get;
set;
}

Currncy Currncy
{
get;
set;
}
void Draw(decimal amount);
void Deposit(decimal amount);
void Transfer(IAccount account, decimal amount);
}

CreditCard类
public class CreditCard : IAccount
{
private Institution bank;
private string name;
private string number;
private Individual holder;
private decimal overdraft;
private decimal cashLimit;
private decimal interestRate;
private int repaymentDay;
private int billDay;
private DateTime startDate;

public DateTime StartDate
{
get { return startDate; }
set { startDate = value; }
}
private decimal amount;
private DateTime expiryMonth;
private Currncy currency;

#region IAccount 成员

public string Name
{
get
{
return name;
}
set
{
name = value;
}
}

public decimal Amount
{
get
{
return amount;
}
set
{
amount = value;
}
}

public Individual Holder
{
get
{
return holder;
}
set
{
holder = value;
}
}

public Currncy Currncy
{
get
{
return currency;
}
set
{
currency = value;
}
}

public void Draw(decimal amount)
{
this.amount = this.amount - amount;
}

public void Deposit(decimal amount)
{
this.amount = this.amount + amount; ;
}

public void Transfer(IAccount account, decimal amount)
{
this.amount = this.amount - amount;
account.Deposit(amount);
}

#endregion
}

用这几个类来表达我想实现的功能是没有问题的,但是确没办法映射到关系型数据库.各个帐户类倒没有问题,现在主要的问题存在于Expense类的持久化.其中IAccount属性没办法用数据表表示,或都说很难表示.

请各位大侠帮忙解决@

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