C# 构造函数中调用虚函数

最新推荐文章于 2025-04-18 00:28:46 发布

原创最新推荐文章于 2025-04-18 00:28:46 发布 · 512 阅读

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本文探讨了在C#中于构造函数内调用虚函数所带来的隐患，特别是当这些函数依赖于子类构造函数初始化的成员变量时。通过一个具体的代码示例，展示了这种做法可能导致意外的行为，并提醒开发者注意此类设计模式的潜在问题。

C# 构造函数中调用虚函数

using System;
using System.Diagnostics;
using System.Text;
using System.Collections;
using System.Collections.Generic;

class Test
{
    public class Base
    {
        public Base()
        {
            System.Console.WriteLine("Base.Base");
            ABitDangerousCall();
        }

        public virtual void ABitDangerousCall()
        {
            System.Console.WriteLine("Base.ABitDangerousCall");
        }

        private class Inner
        {
            public Inner()
            {
                System.Console.WriteLine("Base.Inner.Inner");
            }
        }
        private Inner inner = new Inner();
    }

    class Derived : Base
    {
        public Derived()
        {
            System.Console.WriteLine("Derived.Derived");
            ctorInitializedMember = 5;
        }

        // ctorInitializedMember is default initialized to zero before the constructor initializes it.
        private int ctorInitializedMember;
        private int derivedInt;

        public override void ABitDangerousCall()
        {
            System.Console.WriteLine(String.Format("Derived.ABitDangerousCallctorInitializedMember={0} derivedInt={1}", ctorInitializedMember, derivedInt));
        }

        private class Inner
        {
            public Inner()
            {
                System.Console.WriteLine("Derived.Inner.Inner");
            }
        }
        private Inner inner = new Inner();
    }


    class Program
    {
        static void Main(string[] args)
        {
            Derived d = new Derived();
            Console.Read();
        }
    }

}