C# basic knowledge compilation: basic knowledge (7) hiding of methods

As mentioned in inheritance and abstract classes, there are these relationships between the methods of subclasses and parent classes:
Subclasses directly use parent class methods (but the parent class methods must be public or protected types);
The method of the subclass overrides the method of the parent class (override);
The method of the subclass overrides the method of the parent class (overload);
Look at the following situation:

    public class YSchool
    {
        private int id = 0;

        private string name = string.Empty;

        public int ID
        {
            get
            {
                return this.id;
            }
        }

        public string Name
        {
            get
            {
                return name;
            }
        }

        public YSchool()
        {
            this.id = 0;

            this.name = @"清华大学附中";
        }

        public  YSchool(int id, string name)
        {
            this.id = id;

            this.name = name;
        }

        /// <summary>
        /// 构造器
        /// </summary>
        public  YSchool(int id)
        {
            this.id = id;

            this.name = @"陕师大附中";
        }
    }

    public class YTeacher
    {
        private int id = 0;

        private string name = string.Empty;

        private YSchool school = null;

        private string introDuction = string.Empty;

        private string imagePath = string.Empty;

        public int ID
        {
            get
            {
                return id;
            }
        }

        public string Name
        {
            get
            {
                return name;
            }
        }

        public YSchool School
        {
            get
            {
                if (school == null)
                {
                    school = new YSchool();
                }
                return school;
            }

            set
            {
                school = value;
            }
        }

        public string IntroDuction
        {
            get
            {
                return introDuction;
            }

            set
            {
                introDuction = value;
            }
        }

        public string ImagePath
        {
            get
            {
                return imagePath;
            }

            set
            {
                imagePath = value;
            }
        }
        /// <summary>
        /// 构造器
        /// </summary>
        public YTeacher(int id, string name)
        {
            this.id = id;

            this.name = name;
        }

        /// <summary>
        /// 构造器
        /// </summary>
        public YTeacher(int id, string name, YSchool school)
        {
            this.id = id;

            this.name = name;

            this.school = school;
        }

        /// <summary>
        /// 给学生讲课的方法
        /// </summary>
        public void ToTeachStudents()
        {
            Console.WriteLine(string.Format(@"{0} 老师教育同学们： Good Good Study,Day Day Up!", this.Name));
        }
        /// <summary>
        /// 惩罚犯错误学生的方法
        /// 加virtual关键字，表示该方法可以被覆盖重写
        /// </summary>
        /// <param name="punishmentContent"></param>
        public virtual void PunishmentStudents(string punishmentContent)
        {
            Console.WriteLine(string.Format(@"{0} 的{1} 老师让犯错误的学生 {2}。", this.School.Name, this.name, punishmentContent));
        }
    }

    public class UniversityTeacher : YTeacher
    {
        public UniversityTeacher(int id, string name,YSchool school)

            : base(id, name, school)
        {

        }

        /// <summary>
        /// 隐藏父类的同名方法，隐藏后该类只能访问隐藏后的方法，不能访问到父类的该方法了。
        /// </summary>
        public new void ToTeachStudents()
        {
            Console.WriteLine(string.Format(@"{0} 老师教育同学们：认真学习.net!", this.Name));
        }
        
        /// <summary>
        /// 覆盖
        /// </summary>
        public override void PunishmentStudents(string punishmentContent)
        {
            base.PunishmentStudents(punishmentContent);//也可以不执行父类方法。

            //自己的代码
        }
    }

using System;

namespace YYS.CSharpStudy.MainConsole
{
    class Program
    {
        static void Main(string[] args)
        {
            UniversityTeacher uTeacher = new UniversityTeacher(3, @"董边成", new YSchool(3, @"清华大学"));

            //访问的是子类方法
            uTeacher.ToTeachStudents();
            //可以访问覆盖后的方法
            uTeacher.PunishmentStudents(@"让你挂科。");

            YTeacher teacher = new UniversityTeacher(3, @"董边成", new YSchool(3, @"清华大学"));
            //访问不到隐藏的那个方法了
            teacher.ToTeachStudents();
            //可以访问覆盖后的方法
            teacher.PunishmentStudents(@"跑10000米。");

            Console.ReadKey();
        }
    }
}

Result:

The process of using new to modify a new method with the same name and parameter list as the parent class method is called hiding. That is, the subclass hides this method of the parent class. However, hiding is different from overwriting. A hidden method can only be accessed through the class in which the method is located. If you use variables of the parent class, you will still access the hidden method.
As you can see from the above code, the difference between covering and hiding. After the parent class variable refers to the subclass instance, only the hidden method can be accessed, but the hidden method cannot be accessed. However, the overridden methods can be accessed.
Another point is that if you want this method to be overridden by the subclass, then the parent class must add virtual to the method. You don’t need to add the new keyword to hide the parent class’s method. Hide is generally used less and solves some problems in some special situations.

The above is the summary of C# basic knowledge: the hidden content of basic knowledge (7) method. For more related content, please pay attention to the PHP Chinese website (www.php.cn)!