C# 简易版的计算器程序

今天无聊，用了半个小时帮一个学生写了一个简单的计算器程序。只有最基本的功能，可以供初学者参考。

下面贴上代码：

 public partial class Form1 : Form
    {

        private string FuHao;       //定义操作符号（+，-，*，/）
        private string num1;    //定义第一个参数（就是参与运算的第一个数）
        private string num2;    //定义第二个参数
        private string oldValue = "0";  //定义老参数


        public Form1()
        {
            InitializeComponent();
        }

        //清0操作
        private void btn_Clean_Click(object sender, EventArgs e)
        {
            txt_Vlaue.Text = "0";
            FuHao = string.Empty;
            oldValue = "0";
        }

        //获取结果(=号点击事件)
        private void btn_GetVlaue_Click(object sender, EventArgs e)
        {
            if (FuHao == string.Empty)
            {
                txt_Vlaue.Text = num1.ToString();
            }
            else
            {
                GetValue();
            }
           
        }
        
        //加法操作
        private void btn_add_Click(object sender, EventArgs e)
        {
            if (num2 != null &&　num2 != string.Empty)
            {
                GetValue();
            }
            FuHao = "+";
            oldValue = "0";            
        }

        //减法操作
        private void btn_Jian_Click(object sender, EventArgs e)
        {
            if (num2 != null && num2 != string.Empty)
            {
                GetValue();
            }
            FuHao = "-";
            oldValue = "0";
        }

        //乘法操作
        private void btn_Cheng_Click(object sender, EventArgs e)
        {
            if (num2 != null && num2 != string.Empty)
            {
                GetValue();
            }
            FuHao = "*";
            oldValue = "0";
        }

        //除法操作
        private void btn_Chu_Click(object sender, EventArgs e)
        {
            if (num2 != null && num2 != string.Empty)
            {
                GetValue();
            }
            FuHao = "/";
            oldValue = "0";
        }

        //点击0
        private void btn_0_Click(object sender, EventArgs e)
        {
            InputNum("0");
        }

        //点击1
        private void btn_1_Click(object sender, EventArgs e)
        {
            InputNum("1");
        }

        //点击2
        private void btn_2_Click(object sender, EventArgs e)
        {
            InputNum("2");
        }

        //点击3
        private void btn_3_Click(object sender, EventArgs e)
        {
            InputNum("3");
        }

        //点击4
        private void btn_4_Click(object sender, EventArgs e)
        {
            InputNum("4");
        }

        //点击5
        private void btn_5_Click(object sender, EventArgs e)
        {
            InputNum("5");
        }

        //点击6
        private void btn_6_Click(object sender, EventArgs e)
        {
            InputNum("6");
        }

        //点击7
        private void bvtn_7_Click(object sender, EventArgs e)
        {
            InputNum("7");
        }

        //点击8
        private void btn_8_Click(object sender, EventArgs e)
        {
            InputNum("8");
        }

        //点击9
        private void btn_9_Click(object sender, EventArgs e)
        {
            InputNum("9");
        }

        //小数点点击
        private void btn_point_Click(object sender, EventArgs e)
        {
            InputNum(".");
        }


        //数字点击事件
        public void InputNum(string value)
        {
            //如果已经输入数字，则直接累加
            if (oldValue != "0")
            {
                txt_Vlaue.Text = oldValue + value;
            }
            else
            {
                //如果第一次输入的是小数点
                if (value == ".")
                {
                    txt_Vlaue.Text = "0"+value;
                }
                else
                {
                    txt_Vlaue.Text = value;
                }
            }
            oldValue = txt_Vlaue.Text;
            //如果已经点击了=,-,*,/，那么这个参数是第二个参数
            if (FuHao != null && FuHao.ToString().Trim() != string.Empty )
            {
                num2 = txt_Vlaue.Text;
            }
            else
            {
                num1 = txt_Vlaue.Text;
            }
        }

        //获取值
        private void GetValue()
        {
            double numa = double.Parse(num1);
            double numb = double.Parse(num2);
            double result = 0;
            switch (FuHao)
            {
                case "+":
                    result = numa + numb;
                    break;
                case "-":
                    result = numa - numb;
                    break;
                case "*":
                    result = numa * numb;
                    break;
                default:
                    result = numa / numb;
                    break;
            }
            txt_Vlaue.Text = result.ToString();
            FuHao = string.Empty;
            oldValue = "0";
            num2 = string.Empty;
            num1 = txt_Vlaue.Text;
        }

希望对初学者有帮助。