从基础 class C# 继承字段

Question

I'm having trouble getting a class to inherit fields from its parent class.

I want the BullFrog class and Toad class to inherit all attributes from Amphibian class, and then overwrite the weight attribute. I thought it inherited all traits from the parent class by default, what am I missing here?

public class Animal
    {
        public string sound { get; set; }
        public string move { get; set; }
        public string favSnack { get; set; }
        public double avgWeight { get; set; }
        public void Speak(string sound)
        {
            Console.WriteLine( $"I go {sound}.");
        }
        public void Move(string move)
        {
            Console.WriteLine($"I {this.move} around the farm all day.");
        }
        public void Eat(string favSnack)
        {
            Console.WriteLine($"I like to eat {favSnack}.");
        }
        public void Weight(int avgWeight)
        {
            Console.WriteLine($"I usually weigh about {avgWeight}lbs.");
        }
      
    }
    //decide on four or more animals
    //for each animal decide on four or more methods
    public class Amphibian : Animal
    {
        string sound = "ribbit";
        string move = "hop";
        string favSnack = "flies";
        double avgWeight = .05d;

    }
    public class BullFrog : Amphibian 
    {
        double avgWeight = .375d;
    }

    public class Toad : Amphibian
    {
        double avgWeight = .175d;
    }
    

where did I go wrong? when I call the methods

BullFrog kermit = new BullFrog();
            kermit.Move(kermit.movement);
            kermit.Eat(kermit.favSnack);

I get "I around the farm all day" and two blank lines as the output. My question is

Answer 1

Check the virtual and override keywords in C#. This is to be used in case you want to actually change the way the derived class moves. Go with the constructor way if it's just a string change.

public class Animal
{
     public virtual string move { get; set; }

public class Amphibian : Animal
{
     public override string move { get; set; } =  "hop";

Your line string move = "hop"; is just declaring a private property inside the Amphibian class, which will not affect the base class in any way.

Another way to handle this would be to set the value in a constructor, but you should remember to always set the value in any constructor you are creating.

public class Animal
{
     public string move { get; set; }
 
     public Animal(string move) {
         this.move = move;
     }

And then

public class Amphibian : Animal
{
     public Amphibian(): base("hop") {
     }