using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace lqhJiSuanQi
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        double memoryValue;//存储的值
        string oper;//运算符号
        double inputValue;//正在输入的值
        double cal(string oper, double d1, double d2) //根据oper,计算d1和d2的运算结果
        {
            double result;
            switch (oper)
            {
                case "+":
                    result = d1 + d2;
                    break;
                case "-":
                    result = d1 - d2;
                    break;
                case "*":
                    result = d1 * d2;
                    break;
                case "/":
                    result = d1 / d2;
                    break;
                default:
                    result = d1;
                    break;
            }
            return result;
        }


        private void butEqual_Click(object sender, EventArgs e)//点击等于号：＝ 时
//取出正在输入的值，运算符号，存储的值，计算出结果，
//将结果显示出来，并将结果存储
//作废运算符
        {
            inputValue = Convert.ToDouble(textBox1.Text);
            double result = cal(oper, memoryValue, inputValue);
            textBox1.Text = result.ToString();
            memoryValue = result;
            oper = "";

        }

        private void butClear_Click(object sender, EventArgs e)//C按钮清空输入框
        {
            memoryValue = 0.0;
            inputValue = 0.0;
            textBox1.Text = "";

        }

        private void butDot_Click(object sender, EventArgs e) //点击小数点：. 时
    //如果显示屏上什么也没有，则显示.
    //否则如果有数据，但数据中没有小数点，则附加一个小数点
    //否则什么也不做

        {
            if (textBox1.Text == "")
            {
                textBox1.Text = "0.";
            }
            else if (textBox1.Text.IndexOf('.') < 0)
            {
                textBox1.Text += ".";
            }
            else
                return;

        }

        private void numberButton_Click(object sender, EventArgs e)// 点击: 1，2，3，4，5，6，7，8，9 时
//在原来的显示后面附加所点击的数字

        {
            textBox1.Text += ((Button)sender).Text;
        }

        private void operButton_Click(object sender, EventArgs e)// 点击运算符: +、-、*、/ 时
// 记住数字和运算符，并清空显示屏

        {
            memoryValue = Convert.ToDouble(textBox1.Text);
            oper = ((Button)sender).Text;
            textBox1.Text = "";

        }

        private void zeroButton_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "")
            {
                return;
            }
            else if ((Convert.ToDouble(textBox1.Text) == 0) && (textBox1.Text.IndexOf('.') < 0))
                return;
            else
                textBox1.Text += ((Button)sender).Text;

        }
    }
}

上面是本人用C#写的一个计算器的代码，因为刚刚学，不知道怎么处理异常。请各位赐教。