I have parent class Product and child class DairyProduct and i want to set all fields and properies of parent class in child class, but i do not want to do a lot of new constructors. How to set properties (name, price and weight) in DairyProduct without a new constructor?

Also codes for example:

Parent class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Task1
{
    public class Product
    {
        private string _name;
        public string Name { get => _name; set => _name = value; }

        private float _price;
        public float Price
        {
            get => _price;

            set => _price = value < 0 ? throw new ArgumentException() : _price = value; 
        }

        private float _weight;
        public float Weight
        {
            get { return _weight; }

            set { _weight = value < 0 ? throw new ArgumentException() : _weight = value; }
        }

        public Product() : this(null, default, default) {}

        public Product(string name, float price, float weight) 
        {
            Name = name;
            Price = price;
            Weight = weight;
        }

        public virtual void Discount(float percentage) 
        {
            if (percentage <= 100) Price = Price * (100 - percentage) / 100;
            else throw new ArgumentException();
        
        }

        public override string ToString() 
        {
            return string.Format("Name: {0}; Price: {1}; Weight: {2};", Name, Price, Weight);
        }

        public override bool Equals(object obj)
        {
            if (obj.GetType() != typeof(Product))
            {
                return false;
            }
            else 
            {
                Product p = (Product)obj;
                return p.Name == Name && p.Price == Price && p.Weight == Weight; 
            }
        }
    }
}

Child class

using System;

namespace Task1
{
    class DairyProduct : Product
    {
        public readonly DateTime ExpirationDate;
        private int _daysToExpiration;
        private bool _isFresh;

        public DairyProduct()
        {
            _daysToExpiration = 90;
            ExpirationDate = DateTime.Now.AddDays(_daysToExpiration);
            _isFresh = true;
        }
        public DairyProduct(int daysToExpiration)
        {
            ExpirationDate = DateTime.Now.AddDays(daysToExpiration);
            _isFresh = true;
        }

        public DairyProduct(DateTime experationDate, int daysToExpiration) 
        {
            _daysToExpiration = daysToExpiration;
            ExpirationDate = experationDate;
            CheckExpirationDate();
        }

        public void CheckExpirationDate() => _isFresh = (ExpirationDate - DateTime.Now).Days > 0;

        public override void Discount(float percentage)
        {
            CheckExpirationDate();
            if (_isFresh)
            {
                float discontPersentage = (float)(1 - ((ExpirationDate - DateTime.Now).Days) / _daysToExpiration)   percentage / 100;
                if (discontPersentage >= 1) 
                { 
                    Price = 0;
                }
                else
                {
                    Price *= discontPersentage;
                }
            }
            else 
            {
                Price = 0;
            }
        }

        public override string ToString()
        {
            return string.Format("Name: {0}; Price: {1}; Weight: {2}; Expiration date: {3}", Name, Price, Weight, ExpirationDate);
        }
    }
}

CodePudding user response：

You can include the parent properties with the child constructor parameters. Then call the base() method to initialise the parent properties.

    public DairyProduct(string name, float price, float weight) :
                                             base(name, price, weight)
    {
        _daysToExpiration = 90;
        ExpirationDate = DateTime.Now.AddDays(_daysToExpiration);
        _isFresh = true;
    }

    public DairyProduct(string name, float price, 
                        float weight, int daysToExpiration) : 
                                           base(name, price, weight)
    {
        ExpirationDate = DateTime.Now.AddDays(daysToExpiration);
        _isFresh = true;
    }

    public DairyProduct(string name, float price, float weight,                       
                        DateTime experationDate, int daysToExpiration) : 
                            base(name, price, weight)
    {
        _daysToExpiration = daysToExpiration;
        ExpirationDate = experationDate;
        CheckExpirationDate();
    }