你把计算放在你的集合或你的得分上吗？

Question

哪个更好 ？？？

public class Order
{
   private double _price;
   private double _quantity;

  public double TotalCash
  {      
   get
   {
    return _price * _quantity;
   }
}

要么

public class Order
{

   private double _totalCash;
   private double _price;
   private double _quantity;

  private void CalcCashTotal()
 {
   _totalCash = _price * _quantity
 }

  public double Price
  {      
   set
   {
     _price = value;
     CalcCashTotal();
   }
  }

  public double Quantity
  {      
   set
   {
     _price = value;
     CalcCashTotal();
   }
  }


  public double TotalCash
  {      
   get
   {
    return _totalCash;
   }
}

Answer 1

有权衡.如果计算简单并且不需要很长时间,那就把它放在get中.它让您的生活更轻松,因为您不必担心在总价格依赖的每一组中进行检查,这可能会导致错误.

如果计算需要花费很多时间,那么您也可以采用混合方法.您可以在所有依赖集中设置IsDirtyTotalPrice布尔值,然后在get中进行计算并对其进行缓存,以便get只在需要时计算变量.你没有在集合中进行计算,因为它们可能有很多,你想尽可能少地进行计算.

  public class Order
  {
     private double _totalCash;
     private double _price;
     private double _quantity;
     private _IsDirtyTotalCash = true;

  private void CalcCashTotal()
  {
    _totalCash = _price * _quantity
  }

  public double Price
  {      
   set
   {
     _price = value;
     _IsDirtyTotalCash = true;
   }
  }

  public double Quantity
  {      
   set
   {
     _price = value;
     _IsDirtyTotalCash = true;
   }
  }

  public double TotalCash
  {      
   get
   {
        if(_IsDirtyTotalCash)
    {
      _totalCash = CalcTotalCost();
       _isDirtyTotalCash = false;
     }
     return _totalCash;
   }
  }

}