{C#}设计模式辨析.原型

背景

• 绕过构造器，快速创建已有原型的复制品。
• 复制品可与原型脱勾，独立修改属性或字段。

示例

using static System.Console;

namespace DesignPattern_Prototype
{
    public class Resume
    {
        public string Corp;
        public string Location;

        public override string ToString()
            => $"\n  Corp ={Corp};\n  Location ={Location}";
    }

    public class Person
    {
        public string Name;
        public Resume Resume;

        // 浅拷贝：复制值类型的值，复制引用类型的引用
        public Person ShallowCopy()
            => (Person)MemberwiseClone();

        // 深拷贝：复制所有值，切断引用
        public Person DeepCopy()
        {
            var result = ShallowCopy();
            result.Resume = new Resume();
            result.Resume.Corp = Resume.Corp;
            result.Resume.Location = Resume.Location;

            return result;
        }

        public override string ToString()
            => $"Name ={Name};\nResume ={Resume}";
    }

    class Demo
    {
        static void Main(string[] args)
        {
            var raw = new Person
            {
                Name = "Zhang San",
                Resume = new Resume
                {
                    Corp = "abc",
                    Location = "manager",
                }
            };

            var shallow = raw.ShallowCopy();
            raw.Resume.Corp = "xyz"; // 原稿与浅拷贝同步

            var deep = raw.DeepCopy();
            deep.Name = "Li Shi";
            deep.Resume.Location = "vice president"; // 与原稿异步

            WriteLine("The raw is Printing...");
            WriteLine(raw);

            WriteLine("\nThe shallow copy is Printing...");
            WriteLine(shallow);

            WriteLine("\nThe deep copy is Printing...");
            WriteLine(deep);

            ReadKey();
        }
    }
}