c# - 调用基本构造函数时重用初始化方法

Question

我想使用构造函数在派生类中初始化一个 protected 成员，但是由于我正在调用 base()，所以我不能调用 this()，这使得我的一些调用“有味道”:

public class ABase
    {
        public object Param1 { get; set; }
        public object Param2 { get; set; }
        protected object Param3 { get; set; }

        public ABase()
            : this(null, null)
        { }

        public ABase(object param1)
            : this(param1, null)
        { }

        public ABase(object param1, object param2)
        {
            Param1 = param1;
            Param2 = param2;
        }
    }

    public class A : ABase
    {
        public A()
        { InitParam3(); }

        public A(object param1)
            : base(param1)
        { InitParam3(); }

        public A(object param1, object param2)
            : base(param1, param2)
        { InitParam3(); }

        private void InitParam3()
        {
            Param3 = "param3";
        }
    }

有没有办法避免在每个构造函数中调用 InitParam3()。我对所有设计更改持开放态度。

Answer 1

为子类使用构造函数链，然后调用基类的最完整构造函数。

    public class ABase
        {
            public object Param1 { get; set; }
            public object Param2 { get; set; }
            protected object Param3 { get; set; }

            public ABase()
                : this(null, null)
            { }

            public ABase(object param1)
                : this(param1, null)
            { }

            public ABase(object param1, object param2)
            {
                Param1 = param1;
                Param2 = param2;
            }
        }

        public class A : ABase
        {
            public A() : this(null, null)
            { }

            public A(object param1)
                : this(param1m, null)
            { }

            public A(object param1, object param2)
                : base(param1, param2)
            { InitParam3(); }

            private void InitParam3()
            {
                Param3 = "param3";
            }
        }

更新(删除了重复的默认值):

public abstract class ABase
{
    protected const object DefaultParam1 = null;
    protected const object DefaultParam2 = null;

    public object Param1 {get;set;}
    public object Param2 { get; set; }
    protected object Param3 { get; set; }

    public ABase(object param1 = DefaultParam1, object param2 = DefaultParam2)
    {
        Param1 = param1;
        Param2 = param2;
    }
}

public class A : ABase
{
    public A(object param1 = DefaultParam1, object param2 = DefaultParam2)
        : base(param1, param2)
    {
        Param3 = "param3";
    }       
}