简单工厂模式

namespace SimpleFactory
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Fruits fruits = GetFruit(textBox1.Text);
            fruits.Fruit();
        }

        public Fruits GetFruit(string fruit)
        {
            Fruits fruits = null;

            switch (fruit)
            {
                case "apple":
                    fruits = new Apple();
                    break;
                case "pear":
                    fruits = new Pear();
                    break;
            }

            return fruits;
        }
    }


    public abstract class Fruits
    {
        public virtual void Fruit()
        {
            MessageBox.Show("this is fruit");
        }
    }

    class Apple : Fruits
    {
        public override void Fruit()
        {
            MessageBox.Show("apple");
        }

      
    }

    class Pear : Fruits
    {
        public override void Fruit()
        {
            MessageBox.Show("pear");
        }
    }
}