winform与面向对象应用做一个计算器12月28日

代码部分：

 public partial class 计算器 : Form
    {

        public 计算器()
        {
            InitializeComponent();
        }
        private double sum = 0;//存放运算结果
        private string biaodashi="";//用于存放除了刚点过的运算符的前面表达式部分
        private string preyunsuanfu="";//用来存放上一步运算符，用于下次点运算符的时候算上一步的结果

        private bool isok = false;//用它记录是否是刚开始运行程序，是否刚刚点过运算符

        private void one_Click(object sender, EventArgs e)
        {
            Button btn = (Button)sender;
            if (!isok||textshu.Text=="0")//如果isok是false或者输入框是0那就清空
                textshu.Text = btn.Text;
            else//否则就累加
                textshu.Text += btn.Text;
            isok = true;//凡是点完数字就设置isok为true
        }

        private void jia_Click(object sender, EventArgs e)
        {
            Button btn = (Button)sender;
            if (isok)
            {
                if (biaodashi == "" && preyunsuanfu == "")//第一次点运算符
                {
                    sum = double.Parse(textshu.Text);
                    biaodashi = textshu.Text;
                }

                else//不是第一次点运算，先算上一步运算
                {
                    if (preyunsuanfu == "+")
                    {
                        sum = sum + double.Parse(textshu.Text);
                    }
                    if (preyunsuanfu == "-")
                    {
                        sum = sum - double.Parse(textshu.Text);
                    }
                    if (preyunsuanfu == "*")
                    {
                        sum = sum * double.Parse(textshu.Text);
                    }
                    if (preyunsuanfu == "/")
                    {
                        sum = sum / double.Parse(textshu.Text);
                    }
                    if (preyunsuanfu == "%")
                    {
                        sum = sum % double.Parse(textshu.Text);
                    }
                    biaodashi = biaodashi + preyunsuanfu + textshu.Text;
                }
            }
            txtbiaodashi.Text = biaodashi + btn.Text;//把表达式文本框拼接显示
            preyunsuanfu = btn.Text;//换上一步运算符，将刚才点的运算符，存为上一步运算符
            textshu.Text = sum.ToString();//将下面输入框显示为运算结果
            isok = false;//记录刚刚点过的运算符，以便点数字的时候知道是刚点了运算符
        }

        private void clear_Click(object sender, EventArgs e)
        {
            isok = false;
            biaodashi = "";
            textshu.Text = "0";
            txtbiaodashi.Text = "";
            preyunsuanfu = "";
            sum = 0;
        }

        private void shan_Click(object sender, EventArgs e)
        {
            if (textshu.Text.Length > 1)
            {
                textshu.Text = textshu.Text.Substring(0, textshu.Text.Length - 1);
            }
            else
            {
                textshu.Text = "0";
            }
        }

        private void dian_Click(object sender, EventArgs e)
        {
            if (isok)
            {
                if (!textshu.Text.Contains("."))
                {
                    textshu.Text += ".";
                }
            }
            else
            {
                textshu.Text = "0.";
            }
        }

        private void dengyu_Click(object sender, EventArgs e)
        {
            if (preyunsuanfu == "+")
            {
                sum = sum + double.Parse(textshu.Text);
            }
            if (preyunsuanfu == "-")
            {
                sum = sum - double.Parse(textshu.Text);
            }
            if (preyunsuanfu == "*")
            {
                sum = sum * double.Parse(textshu.Text);
            }
            if (preyunsuanfu == "/")
            {
                sum = sum / double.Parse(textshu.Text);
            }
            if (preyunsuanfu == "%")
            {
                sum = sum % double.Parse(textshu.Text);
            }
            biaodashi = "";
            preyunsuanfu = "";
            txtbiaodashi.Text = "";
            textshu.Text = sum.ToString();
            isok = false;
        }

    }

效果如下：