计算器的简单编写,熟悉访问器,重载

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

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

        private void comboBox1_DrawItem(object sender, DrawItemEventArgs e) //修改combox 信息 中间显示
        {
            string s = this.comboBox1.Items[e.Index].ToString();
            SizeF ss = e.Graphics.MeasureString(s, e.Font);

            float l = (float)(e.Bounds.Width - ss.Width) / 2;
            if (l < 0) l = 0f;
            float t = (float)(e.Bounds.Height - ss.Height) / 2;
            if (t < 0) t = 0f;
            t = t + this.comboBox1.ItemHeight * e.Index;
            e.DrawBackground();
            e.DrawFocusRectangle();
            e.Graphics.DrawString(s, e.Font, new SolidBrush(e.ForeColor), l, t);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.comboBox1.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            int str1 = Convert.ToInt32(textBox1.Text);
            int str2 = Convert.ToInt32(textBox2.Text);

            Jisuan jisuan = new Jisuan(Convert.ToInt32(str1), Convert.ToInt32(str2));
            switch (comboBox1.Text)
            {

                case "+": label1.Text = jisuan.Add().ToString(); break;

            }
        }
    }
}

类:

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

namespace 计算器
{
    public class Jisuan
    {

        public Jisuan(int str1, int str2)
        {
            this.Number1 = str1;
            this.Number2 = str2;

        }

        public int Number1
        {

            get ;
            set;

        }

        public int Number2
        {

            get;
            set;

        }

        public int Add()
        {

            return Number1 + Number2;

        }

    }
}