3月8日 第一个winform程序（计算器）

初始界面

代码：

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 bool isok = true;      //用来判断是否刚刚点过运算符
        private string biaodashi;     //表达式
        private double sum = 0;      //记录运算的结果
        private string Preyunsuanfu;//记录上一个运算符

        private string btnow = "";//记录刚输入的数字

        #region
        //数字输入
        private void no0_Click(object sender, EventArgs e)
        {
            Button btn = (Button)sender;
            btnow = btn.Text;

            if (shuru.Text != "0")
            {
                if (isok)
                {
                    shuru.Text = btn.Text.ToString();
                    isok = false;
                }
                else
                {
                    shuru.Text += btn.Text.ToString();
                }
            }
            else
            {
                if (isok)
                {
                    shuru.Text = "";
                    shuru.Text = btn.Text;
                    isok = false;
                }
                else
                {
                    shuru.Text = "";
                    shuru.Text += btn.Text;
                }
            }
        }
        #endregion
        #region
        //运算符
        private void btjia_Click(object sender, EventArgs e)
        {
            Button btn = (Button)sender;
            string yunsuanfu = btn.Text;

            if (Preyunsuanfu == null)
            {
                biaodashi += shuru.Text;
                sum = double.Parse(shuru.Text);
            }
            else
            {
                if (!isok)
                {
                    if (Preyunsuanfu == "+")
                    {
                        sum += double.Parse(shuru.Text);
                    }
                    if (Preyunsuanfu == "-")
                    {
                        sum -= double.Parse(shuru.Text);
                    }
                    if (Preyunsuanfu == "*")
                    {
                        sum *= double.Parse(shuru.Text);
                    }
                    if (Preyunsuanfu == "/")
                    {
                        sum /= double.Parse(shuru.Text);
                    }
                    if (Preyunsuanfu == "%")
                    {
                        sum %= double.Parse(shuru.Text);
                    }
                    biaodashi = biaodashi + Preyunsuanfu + shuru.Text;
                    shuru.Text = sum.ToString();
                }
            }
            shuchu.Text = biaodashi + yunsuanfu;
            Preyunsuanfu = yunsuanfu;
            isok = true;
        }
        #endregion
        #region
        //退格
        private void tuige_Click(object sender, EventArgs e)
        {      
           int geshu= shuru.Text.ToString().Length;
            string str = shuru.Text.ToString();
            if (geshu > 1)
            {
                str = str.Remove(geshu - 1, 1);
                shuru.Text = str;
            }
            else
            {
                shuru.Text = "0";
            }
        }
        #endregion
        #region
        //清空
        private void clear_Click(object sender, EventArgs e)
        {
            shuru.Text = "0";
            shuchu.Text = "";
            sum = 0;
            biaodashi = "";
            Preyunsuanfu = "";
        }
        #endregion
        #region
        //等于
        private void equal_Click(object sender, EventArgs e)
        {
            shuchu.Text = "";
            if (Preyunsuanfu == "+")
            {
                shuru.Text = (sum + double.Parse(btnow)).ToString();
            }
            if (Preyunsuanfu == "-")
            {
                shuru.Text = (sum - double.Parse(btnow)).ToString();
            }
            if (Preyunsuanfu == "*")
            {
                shuru.Text = (sum * double.Parse(btnow)).ToString();
            }
            if (Preyunsuanfu == "/")
            {
                shuru.Text = (sum / double.Parse(btnow)).ToString();
            }
            if (Preyunsuanfu == "%")
            {
                shuru.Text = (sum % double.Parse(btnow)).ToString();
            }
        }
        #endregion
        #region
        //小数点
        //private string dian = "";
        private void point_Click(object sender, EventArgs e)
        {
            Button btn = (Button)sender;
            string predian = btn.Text;

            shuru.Text += btn.Text;

        }
        #endregion
    }
}