继承

代码示例

1public class Car
2{
3    public string Model { get; set; }
4    public decimal Price { get; set; }
5    public int Year { get; set; }
6    public int FuelCapacityInLiters { get; set; }
7    public int FuelLeft { get; set; }
8
9    public void Drive()
10    {
11    }
12}

1namespace Inheritance
2{
3    public class Vehicle
4    {
5        public string Model { get; set; }
6        public decimal Price { get; set; }
7        public int Year { get; set; }
8        public int FuelCapacityInLiters { get; set; }
9        public int FuelLeft { get; set; }
10        public short NumberOfWheels { get; set; }
11        
12        public void Drive()
13        {
14        }
15    }
16}

1namespace Inheritance
2{
3    // Car 继承自 Vehicle
4    // Vehicle 是 Car 的基类
5    public class Car : Vehicle
6    {
7    }
8}

1namespace Inheritance
2{
3    public class Motorcycle : Vehicle
4    {
5    }
6}

1using Inheritance;
2
3// 创建 Car 实例
4Car myCar = new Car();
5myCar.Model = "Toyota Prius";
6myCar.Price = 12000;
7
8Console.WriteLine($"{myCar.Model} costs {myCar.Price} dollars.");
9
10// 创建 Motorcycle 实例
11Motorcycle myBike = new Motorcycle();
12myBike.Model = "Harley Davidson";
13myBike.Price = 20000;
14
15Console.WriteLine($"{myBike.Model} costs {myBike.Price} dollars.");

代码示例

1Vehicle myCar = new Car();

从 System.Object 的隐式继承

1// 从 Object 继承
2public class SomeClass
3{
4}

1using Inheritance;
2
3Car myCar = new Car();
4Car anotherCar = new Car();
5
6// 调用 Object 类的方法
7Console.WriteLine(myCar.ToString());
8Console.WriteLine(myCar.Equals(anotherCar));
9Console.WriteLine(myCar.GetHashCode());
10Console.WriteLine(myCar.GetType());

1public sealed class SomeClass
2{
3}
4
5public class MyClass : SomeClass // 错误：无法从密封类型 'SomeClass' 继承
6{
7}

使用组合包含功能

1namespace Inheritance;
2
3public class Engine
4{
5    public void Start() 
6    {
7        Console.WriteLine("引擎启动。");
8    }
9}
10
11// 组合：Car “拥有一个” 引擎
12public class Car : Vehicle
13{
14    public Engine CarEngine { get; set; } = new Engine();
15    public int NumberOfDoors { get; set; }
16}