如何使用 C# 实现开闭原则?
csharpserver side programmingprogramming更新于 2025/6/2 17:22:17
类、模块和函数等软件实体应该对扩展开放，但对修改关闭。
定义 − 开闭原则指出，代码的设计和编写应以尽可能少地更改现有代码的方式添加新功能。设计应允许以新类的形式添加新功能，同时尽可能保持现有代码不变。
示例
先写代码，后开闭原则
using System;
using System.Net.Mail;
namespace SolidPrinciples.Open.Closed.Principle.Before{
public class Rectangle{
public int Width { get; set; }
public int Height { get; set; }
}
public class CombinedAreaCalculator{
public double Area (object[] shapes){
double area = 0;
foreach (var shape in shapes){
if(shape is Rectangle){
Rectangle rectangle = (Rectangle)shape;
area += rectangle.Width * rectangle.Height;
}
}
return area;
}
}
public class Circle{
public double Radius { get; set; }
}
public class CombinedAreaCalculatorChange{
public double Area(object[] shapes){
double area = 0;
foreach (var shape in shapes){
if (shape is Rectangle){
Rectangle rectangle = (Rectangle)shape;
area += rectangle.Width * rectangle.Height;
}
if (shape is Circle){
Circle circle = (Circle)shape;
area += (circle.Radius * circle.Radius) * Math.PI;
}
}
return area;
}
}
}
遵循开放关闭原则的代码
namespace SolidPrinciples.Open.Closed.Principle.After{
public abstract class Shape{
public abstract double Area();
}
public class Rectangle: Shape{
public int Width { get; set; }
public int Height { get; set; }
public override double Area(){
return Width * Height;
}
}
public class Circle : Shape{
public double Radius { get; set; }
public override double Area(){
return Radius * Radius * Math.PI;
}
}
public class CombinedAreaCalculator{
public double Area (Shape[] shapes){
double area = 0;
foreach (var shape in shapes){
area += shape.Area();
}
return area;
}
}
}
