问使用静态类和重写值

EN

public static List<Pet> LoadPetDetails(string filename)
    {
        RegisterPet("Sheep", typeof(Sheep));
        RegisterPet("Dog", typeof(Dog));
        RegisterPet("Cat", typeof(Cat));
        RegisterPet("Rabbit", typeof(Rabbit));

        StreamReader reader = new StreamReader(filename);
        string kind, name, id, breed, desc;
        int age;
        bool gender;
        petSize size;
        List<string> petTraits = new List<string>();
        List<string> require = new List<string>();
        List<Pet> loadedPets = new List<Pet>();

        try
        {
            //read in the count of how many pets in care currently
            int count = Convert.ToInt32(reader.ReadLine());

            //read in details for pet 1 through to we reach the count 
            for (int j = 1; j <= count; j++)
            {
                //clear both of these list from the previous pet
                petTraits.Clear();
                require.Clear();

                //read in the kind
                kind = reader.ReadLine();
                //read in name
                name = reader.ReadLine();
                //read in id
                id = reader.ReadLine();
                //read in the pet traits
                for (int i = 0; i <= 2; i++)
                    petTraits.Add(reader.ReadLine());
                //read in pet breed
                breed = reader.ReadLine();
                //read in the pet's description
                desc = reader.ReadLine();
                //read in list of requirments
                for (int i = 0; i <= 1; i++)
                    require.Add(reader.ReadLine());
                //read in age
                age = Convert.ToInt32(reader.ReadLine());
                //read in size
                size = ConvertToPetSize(reader.ReadLine());
                //read in gender
                gender = Convert.ToBoolean(reader.ReadLine());

                //create the pet and add it to the list of pets to return
                loadedPets.Add(Pet.CreatePet(kind, name, id, petTraits, breed, desc, require, age, size, gender));
            }
        }
        finally
        {
            reader.Close();
        }
        return loadedPets;
    }