简单计算器

简单计算器，暂时label控件的显示功能还不完善，不想了，就这样

界面设计：

显示计算公式：lblShow

显示按下的数字和结果：txtShow

0-9按钮：btnZero~btnNine

按钮点：btnPoint

加：btnAdd

减：btnMinus

乘：btnMultiply

除：btnDivided

回退：btnFallback

CE按钮：btnCE

C按钮：btnC

等于按钮：btnEqual

为防止误操作，把文本框的属性设置成不可手动修改：

原文本框高度太小，属性修改：

详细代码：

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 Counter : Form
    {
        public Counter()
        {
            InitializeComponent();
        }
        //设置全局变量
        //加减乘除运算符
        string Operator;
        //前数值
        decimal FrontValue;
        //后数值
        decimal BehindValue;
        //判断已有小数点
        bool AlreadyPoint=false;
        //判断已等于
        bool AlreadyEqual = false;

        private void Counter_Load(object sender, EventArgs e)
        {
            lblShow.Text = "";
        }

        private void btnZero_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 0;
            lblShow.Text += 0;
        }

        private void btnOne_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 1;
            lblShow.Text += 1;
        }

        private void btnTwo_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 2;
            lblShow.Text += 2;
        }

        private void btnThree_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 3;
            lblShow.Text += 3;
        }

        private void btnFour_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 4;
            lblShow.Text += 4;
        }

        private void btnFive_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 5;
            lblShow.Text += 5;
        }

        private void btnSix_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 6;
            lblShow.Text += 6;
        }

        private void btnSeven_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 7;
            lblShow.Text += 7;
        }

        private void btnEight_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 8;
            lblShow.Text += 8;
        }

        private void btnNine_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
                lblShow.Text = "";
                AlreadyEqual = false;
            }
            txtShow.Text += 9;
            lblShow.Text += 9;
        }

        private void btnPoint_Click(object sender, EventArgs e)
        {
            if (AlreadyEqual == true)
            {
                txtShow.Text = "";
            }
            if (txtShow.Text != "" && AlreadyPoint==false)
            {
                AlreadyPoint = true;
                txtShow.Text += ".";
            }
        }
        //加
        private void btnAdd_Click(object sender, EventArgs e)
        {
            if (txtShow.Text != "")
            {
                FrontValue += decimal.Parse(txtShow.Text);
                txtShow.Text = "";
                lblShow.Text += " + ";
                Operator = "add";
                AlreadyPoint = false;
            }
        }
        //减
        private void btnMinus_Click(object sender, EventArgs e)
        {
            if (txtShow.Text != "")
            {
                FrontValue += decimal.Parse(txtShow.Text);
                txtShow.Text = "";
                lblShow.Text += " - ";
                Operator = "Minus";
                AlreadyPoint = false;
            }
        }
        //乘
        private void btnMultiply_Click(object sender, EventArgs e)
        {
            if (txtShow.Text != "")
            {
                FrontValue += decimal.Parse(txtShow.Text);
                txtShow.Text = "";
                lblShow.Text += " * ";
                Operator = "Multiply";
                AlreadyPoint = false;
            }
        }
        //除
        private void btnDivided_Click(object sender, EventArgs e)
        {
            if (txtShow.Text != "")
            {
                FrontValue += decimal.Parse(txtShow.Text);
                txtShow.Text = "";
                lblShow.Text += " / ";
                Operator = "Divided";
                AlreadyPoint = false;
            }
        }
        //等于
        private void btnEqual_Click(object sender, EventArgs e)
        {
            switch(Operator)
            {
                case "add":
                BehindValue = FrontValue + decimal.Parse(txtShow.Text);
                break;
                case "Minus":
                BehindValue = FrontValue - decimal.Parse(txtShow.Text);
                break;
                case "Multiply":
                BehindValue = FrontValue * decimal.Parse(txtShow.Text);
                break;
                case "Divided":
                BehindValue = FrontValue / decimal.Parse(txtShow.Text);
                break;
            }
            txtShow.Text = BehindValue.ToString();
            FrontValue = 0;
            AlreadyEqual = true;
            AlreadyPoint = false;
            lblShow.Text = txtShow.Text;
        }
        //CE清除当前数
        private void btnCE_Click(object sender, EventArgs e)
        {
            txtShow.Text = "";
            //清除功能对lblShow缺失，没想到好方法
            lblShow.Text = "";
        }
        //C全清
        private void btnC_Click(object sender, EventArgs e)
        {
            txtShow.Text = "";
            lblShow.Text = "";
            //加减乘除运算符
            Operator="";
            //前数值
            FrontValue=0;
            //后数值
            BehindValue=0;
            //判断已有小数点
            AlreadyPoint = false;
            //判断已等于
            AlreadyEqual = false;
        }
        //回退功能
        private void btnFallback_Click(object sender, EventArgs e)
        {
            if (txtShow.Text != "")
            {
                txtShow.Text = txtShow.Text.Substring(0, txtShow.Text.Length-1);
                lblShow.Text = lblShow.Text.Substring(0, lblShow.Text.Length - 1);
            }
        }
    }
}

运行效果：

附源码下载：

简单计算器.rar