典型代码-结构与类-2

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace GetTAreaByClass

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            TrapeziaArea myclass = new TrapeziaArea();//实例化类对象

            myclass.SD = Convert.ToDouble(textBox1.Text);//为梯形的上底赋值

            myclass.XD = Convert.ToDouble(textBox2.Text);//为梯形的下底赋值

            myclass.Height = Convert.ToDouble(textBox3.Text);//为梯形的高赋值

            textBox4.Text = myclass.Area().ToString();//计算梯形面积

        }

    }

    class Trapezia//自定义类

    {

        private double sd = 0;//定义int型变量，作为梯形的上底

        private double xd = 0;//定义int型变量，作为梯形的下底

        private double height = 0;//定义int型变量，作为梯形的高

        /// <summary>

        /// 上底

        /// </summary>

        public double SD

        {

            get

            {

                return sd;

            }

            set

            {

                sd = value;

            }

        }

        /// <summary>

        /// 下底

        /// </summary>

        public double XD

        {

            get

            {

                return xd;

            }

            set

            {

                xd = value;

            }

        }

        /// <summary>

        /// 高

        /// </summary>

        public double Height

        {

            get

            {

                return height;

            }

            set

            {

                height = value;

            }

        }

    }

    /// <summary>

    /// 自定义类，该类继承自Trapezia

    /// </summary>

    class TrapeziaArea : Trapezia

    {

        /// <summary>

        /// 求梯形的面积

        /// </summary>

        /// <returns>梯形的面积</returns>

        public double Area()

        {

            return (SD + XD) * Height / 2;

        }

    }

}