我有抽象基类,包含一些字段和一些作用于这些字段的方法.例如：
- public abstract class A
- {
- protected double _field;
- public double SquaredField { get { return _field * _field; } }
- ... some other abstract methods
- }
我想强制A的所有孩子在他们的构造函数中初始化_field
- public class B : A
- {
- public B(double field)
- {
- _field = Math.Sqrt(field);
- }
- ... some other method implementations
- }
实现这一目标的正确模式是什么？
– 编辑
我最终做的是：
- public abstract class A
- {
- protected readonly double _field;
- public A(double field)
- {
- _field = field;
- }
- public double SquaredField { get { return _field * _field; } }
- ... some other abstract methods
- }
- public class B : A
- {
- public B(double field) : base(field)
- {
- }
- public static B CreateNew(double val)
- {
- return new B(Math.Sqrt(field));
- }
- ... some other method implementations
- }
解决方法
根本不要将字段公开给派生类.相反,创建一个受保护的抽象属性：
- public abstract class A
- {
- protected double Field { get; }
- public double SquaredField { get { return Field * Field; } }
- }
或者,如果字段对于特定实例应始终保持不变,请将其作为构造函数参数并将其保持为私有：
- public abstract class A
- {
- private readonly double _field;
- public double SquaredField { get { return _field * _field; } }
- protected A(double field)
- {
- _field = field;
- }
- }
