第二个作品（宝宝的计算器1.0）

代码还在测试当中，请大家多多发现BUG！

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

namespace WindowsApplication13
{
    public partial class Form1 : Form
    {

        public Form1()
        {
            InitializeComponent();
        }

        public string number, Temp, dengyu;
        public double number1, number2, result;
        public int SymbolsJudgement=0,lian = 0;
        public bool xiaoshudian;

        private void Form1_Load(object sender, EventArgs e)
        {
            TextBox.Text = "0";
            this.KeyDown += new KeyEventHandler(Form1_KeyDown);
        }

        void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            string i;
            switch (e.KeyCode)
            {
                case Keys.D1: i = "1"; this.method(i); break;
                case Keys.D2: i = "2"; this.method(i); break;
                case Keys.D3: i = "3"; this.method(i); break;
                case Keys.D4: i = "4"; this.method(i); break;
                case Keys.D5: i = "5"; this.method(i); break;
                case Keys.D6: i = "6"; this.method(i); break;
                case Keys.D7: i = "7"; this.method(i); break;
                case Keys.D8: i = "8"; this.method(i); break;
                case Keys.D9: i = "9"; this.method(i); break;
                case Keys.D0: button10_Click(sender, e); break;
                case Keys.Add: button11_Click(sender, e); break;
                case Keys.Subtract: button12_Click(sender, e); break;
                case Keys.Multiply: button13_Click(sender, e); break;
                case Keys.Divide: button14_Click(sender, e); break;
                case Keys.NumPad1: i = "1"; this.method(i); break;
                case Keys.NumPad2: i = "2"; this.method(i); break;
                case Keys.NumPad3: i = "3"; this.method(i); break;
                case Keys.NumPad4: i = "4"; this.method(i); break;
                case Keys.NumPad5: i = "5"; this.method(i); break;
                case Keys.NumPad6: i = "6"; this.method(i); break;
                case Keys.NumPad7: i = "7"; this.method(i); break;
                case Keys.NumPad8: i = "8"; this.method(i); break;
                case Keys.NumPad9: i = "9"; this.method(i); break;
                case Keys.NumPad0: button10_Click(sender,e); break;
                case Keys.Back: Backspace_Click(sender,e); break;
                case Keys.Enter: button15_Click(sender,e); break;
                case Keys.Decimal: point_Click(sender, e); break;
                case Keys.Delete: clear_Click(sender,e); break;
            }
        }

        private void method(string i)
        {
            if (TextBox.Text == "0")
            {
                xiaoshudian = false;
                number = i;
                TextBox.Text = Convert.ToString(number);
            }
            else
            {
                number = number + i;
                TextBox.Text = number;
            }
        }

        private void button_click(object sender, EventArgs e)
        {
            string i;
            Button btn = sender as Button;
            string num = btn.Name.Substring(btn.Name.Length - 1);
            switch (num)
            {
                case "1": i = "1"; this.method(i); break;
                case "2": i = "2"; this.method(i); break;
                case "3": i = "3"; this.method(i); break;
                case "4": i = "4"; this.method(i); break;
                case "5": i = "5"; this.method(i); break;
                case "6": i = "6"; this.method(i); break;
                case "7": i = "7"; this.method(i); break;
                case "8": i = "8"; this.method(i); break;
                case "9": i = "9"; this.method(i); break;
            }
        }

        private void button10_Click(object sender, EventArgs e)
        {
            if (TextBox.Text != "0")
            {
                number = number + "0";
                TextBox.Text = number;
            }
            else
            {
                xiaoshudian = false;
            }
        }

        private void yunsuan(int j)
        {
            xiaoshudian = false;
            if (lian == 0)
            {
                SymbolsJudgement = j;
                if (number == "")
                {
                    number = "0";
                }
                number1 = Convert.ToDouble(number);
                lian++;
                number = "";
            }
            else
            {
                number = "0";
                if (SymbolsJudgement == 1)
                {
                    if (number == "")
                    {
                        number = "0";
                    }
                    result = Convert.ToDouble(Convert.ToDouble(number1) + Convert.ToDouble(number));
                    number1 = result;
                    TextBox.Text = Convert.ToString(result);
                    number = "";
                }
                else if (SymbolsJudgement == 2)
                {
                    if (number == "")
                    {
                        number = "0";
                    }
                    result = Convert.ToDouble(Convert.ToDouble(number1) - Convert.ToDouble(number));
                    number1 = result;
                    TextBox.Text = Convert.ToString(result);
                    number = "";
                }
                else if (SymbolsJudgement == 3)
                {
                    if (number == "0")
                    {
                        number = "1";
                    }
                    if (number == "")
                    {
                        number = "0";
                    }
                    result = Convert.ToDouble(Convert.ToDouble(number1) * Convert.ToDouble(number));
                    number1 = result;
                    TextBox.Text = Convert.ToString(result);
                    number = "";
                }
                else if (SymbolsJudgement == 4)
                {
                    if (number == "0")
                    {
                        number = "1";
                    }
                    if (number == "")
                    {
                        number = "1";
                    }
                    result = Convert.ToDouble(Convert.ToDouble(number1) / Convert.ToDouble(number));
                    number1 = result;
                    TextBox.Text = Convert.ToString(result);
                    number = "";
                }
                SymbolsJudgement = j;
            }
        }

        private void button11_Click(object sender, EventArgs e)
        {
            int j = 1;this.yunsuan(j);
        }

        private void button12_Click(object sender, EventArgs e)
        {
            int j = 2;this.yunsuan(j);
        }

        private void button13_Click(object sender, EventArgs e)
        {
            int j = 3;this.yunsuan(j);
        }

        private void button14_Click(object sender, EventArgs e)
        {
            int j = 4;this.yunsuan(j);
        }

        private void button15_Click(object sender, EventArgs e)
        {
            xiaoshudian = false;
            switch (SymbolsJudgement)
            {
                case 1:
                    dengyu = Convert.ToString(number1 + Convert.ToDouble(number));
                    TextBox.Text = Convert.ToString(number1 + Convert.ToDouble(number));
                    break;
                case 2:
                    dengyu = Convert.ToString(number1 - Convert.ToDouble(number));
                    TextBox.Text = Convert.ToString(number1 - Convert.ToDouble(number));
                    break;
                case 3:
                    dengyu = Convert.ToString(number1 * Convert.ToDouble(number));
                    TextBox.Text = Convert.ToString(number1 * Convert.ToDouble(number));
                    break;
                case 4:
                    if (TextBox.Text == "0")
                    {
                        TextBox.Text = "除数不能为0";
                        break;
                    }
                    else
                    {
                        dengyu = Convert.ToString(number1 / Convert.ToDouble(number));
                        TextBox.Text = Convert.ToString(number1 / Convert.ToDouble(number));
                        break;
                    }
            }
            number1 = Convert.ToDouble(dengyu);
        }

        private void clear_Click(object sender, EventArgs e)
        {
            number = ""; TextBox.Text = "0"; result = 0.0; number1 = 0.0; lian = 0; number2 = 0.0;
        }

        private void point_Click(object sender, EventArgs e)
        {
            if (xiaoshudian == false)
            {
                if (TextBox.Text == "0")
                {
                    number += "0.";
                }
                else
                {
                    number += ".";
                }
            }
            xiaoshudian = true;
            TextBox.Text = Convert.ToString(number);
        }

        private void Backspace_Click(object sender, EventArgs e)
        {
            if (TextBox.Text != "0")
            {
                number2 = Convert.ToDouble(TextBox.Text);
                number = Convert.ToString((number2 - number2 % 10) / 10);
                TextBox.Text = Convert.ToString(number);
            }
            if (TextBox.Text == "0")
            {
                number = "";TextBox.Text = "0";result = 0.0;number1 = 0.0;lian = 0;number2 = 0.0;
            }
        }

        private void negative_Click(object sender, EventArgs e)
        {

            number = Convert.ToString(0 - Convert.ToDouble(TextBox.Text));
            TextBox.Text = Convert.ToString(number);
        }

        private void sqrt_Click(object sender, EventArgs e)
        {
            if (Convert.ToDouble(TextBox.Text) < 0)
            {
                this.TextBox.Text = "负数不能平方根";
            }
            else
            {
                number2 = Convert.ToDouble(TextBox.Text);
                TextBox.Text = Convert.ToString(System.Math.Sqrt(number2));
                number = TextBox.Text;
                xiaoshudian = true;
            }
        }

        private void 关于作者ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            help helps = new help();
            helps.Show();
        }

        private void 复制ToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            Temp = TextBox.Text;
        }

        private void 粘贴ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            TextBox.Text = Temp;
        }
    }
}