学习C#自作计算器，菜鸟初学，有大神的指点，希望做的不够好的地方请大家多多指导。同时希望非常无聊的大神能加些其它计算进去

namespace windowsformsapplication15
{
    public partial class 祥哥计算器 : form
    {
        public 祥哥计算器()
        {
            initializecomponent();
        }

        #region 数字点击事件
        /// <summary>
        /// 按钮点击事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "1";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "1";
                setnum(textbox2.text);
            }
        }
        private void button2_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "2";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "2";
                setnum(textbox2.text);
            }
        }
        private void button3_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "3";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "3";
                setnum(textbox2.text);
            }
        }
        private void button4_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "4";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "4";
                setnum(textbox2.text);
            }
        }
        private void button5_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "5";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "5";
                setnum(textbox2.text);
            }
        }
        private void button7_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "7";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "7";
                setnum(textbox2.text);
            }
        }
        private void button6_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "6";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "6";
                setnum(textbox2.text);
            }
        }
        private void button8_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "8";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "8";
                setnum(textbox2.text);
            }
        }
        private void button9_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "9";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "9";
                setnum(textbox2.text);
            }
        }
        private void button14_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "0";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "0";
                setnum(textbox2.text);
            }
        }
     /// <summary>
     /// 小数点问题
     /// </summary>
     /// <param name="sender"></param>
     /// <param name="e"></param>
     private void buttonpoint_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += ".";
                //if(textbox1.text.indexof(".") >= 1)
                //    messagebox.show("已经有小数点了");
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += ".";
                //if(textbox2.text.indexof(".") >=1)
                //    messagebox.show("已经有小数点了");
                    setnum(textbox2.text);
            }
        }
        private void button00_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "00";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "00";
                setnum(textbox2.text);
            }
        }
        private void buttona_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "a";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "a";
                setnum(textbox2.text);
            }
        }

        private void buttonb_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "b";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "b";
                setnum(textbox2.text);
            }
        }

        private void buttonc_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "c";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "c";
                setnum(textbox2.text);
            }
        }

        private void buttond_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "d";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "d";
                setnum(textbox2.text);
            }
        }

        private void buttone_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "e";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "e";
                setnum(textbox2.text);
            }
        }

        private void buttonf_click(object sender, eventargs e)
        {
            if (string.isnullorwhitespace(label1.text))
            {
                if (textbox1.text.length < 10)
                    textbox1.text += "f";
                setnum(textbox1.text);
            }
            else
            {
                if (textbox2.text.length < 10)
                    textbox2.text += "f";
                setnum(textbox2.text);
            }
        }
        /// <summary>
        /// 清空键与退格键
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button16_click_1(object sender, eventargs e)     ///清空ce键
        {
            label1.text = "";
            textbox3.clear();
            textbox1.clear();
            textbox2.clear();
        }
        private void buttondelete_click(object sender, eventargs e)    ///退格键
        {
            if (string.isnullorwhitespace(label1.text))
            {
                textbox1.text = textbox1.text.substring(0, textbox1.text.length - 1);
            }
            else
            {
                textbox2.text = textbox2.text.substring(0, textbox2.text.length - 1);
            }
        }
        #endregion
        /// <summary>
        /// 读取数字功能
        /// </summary>
        /// <param name="text"></param>
        private void setnum(string text)    ///调用功能键
        {
            {
                if (string.isnullorwhitespace(label1.text))
                {
                    textbox1.text = text;
                }
                else
                {
                    textbox2.text = text;
                }
            }
        }
    /// <summary>
    /// 四则运算
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void button10_click(object sender, eventargs e)         ///运算符号
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))
            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
            }
            label1.text = "+";
        }
     private void button11_click(object sender, eventargs e)
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))

            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
                label1.text = "-";
            }
            //else
            //    label1.text = "-";
            else if (string.isnullorwhitespace(label1.text))

                if (string.isnullorwhitespace(textbox1.text))
                {
                    textbox1.text += "-";
                }
                 else
                    label1.text = "-"; 
            //else if (string.isnullorwhitespace(textbox2.text))
                 else
                textbox2.text += "-"; 
        }
    private void button15_click(object sender, eventargs e)
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))
            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
            }
            label1.text = "×";
        }
    private void button13_click(object sender, eventargs e)
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))
            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
            }
            label1.text = "÷";
        }
     /// <summary>
     /// 幂次与根号运算（目前只运算正根号）
     /// </summary>
     /// <param name="sender"></param>
     /// <param name="e"></param>
     private void buttonmi_click(object sender, eventargs e)
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))
            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
            }
            label1.text = "aⁿ";
        }
     private void buttongenhao_click(object sender, eventargs e)
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))
            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
            }
            label1.text = "√￣";
        }
    /// <summary>
    /// 4种数据转换
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void buttonbool_click(object sender, eventargs e)
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))
            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
            }
            label1.text = "dto2";
        }
    private void buttonhex_click(object sender, eventargs e)
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))
            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
            }
            label1.text = "dtoff";
        }
    private void button2tod_click(object sender, eventargs e)
        {
            label1.text = "2tod";
        }
    private void buttonfftod_click(object sender, eventargs e)
        {
            if (!string.isnullorwhitespace(textbox1.text) && !string.isnullorwhitespace(textbox2.text))
            {
                textbox1.text = textbox3.text;
                textbox2.text = "";
            }
            label1.text = "fftod";
        }
  /// <summary>
  /// 计算结果
  /// </summary>
  /// <param name="sender"></param>
  /// <param name="e"></param>
  private void button12_click(object sender, eventargs e)     ///=号控制
        {
             int32 sum1; string str1;
            switch (label1.text)
            {
                case "dto2":
                    sum1 = convert.toint32(textbox1.text);
                    textbox3.text = convert.tostring(sum1, 2);
                    break;
                case "dtoff":
                    sum1 = convert.toint32(textbox1.text);
                    textbox3.text = convert.tostring(sum1, 16);
                    textbox3.text = textbox3.text.toupper();
                    break;
                case "2tod":
                    str1 = convert.tostring(textbox1.text);
                    textbox3.text = convert.toint32(str1, 2).tostring();
                    break;
                case "fftod":
                    str1 = convert.tostring(textbox1.text);
                    textbox3.text = convert.toint32(str1, 16).tostring();
                    break;
                default:
                    textbox3.text = calnum(convert.todouble(textbox1.text), convert.todouble(textbox2.text));
                    break;
            }
        }
  /// <summary>
    /// 计算算法
    /// </summary>
    /// <param name="num1"></param>
    /// <param name="num2"></param>
    /// <returns></returns>
    private string calnum(double num1, double num2) /// 计算
        {
            double sum = 0;
            switch (label1.text)
            {
                case "+":
                    sum = num1 + num2;
                    break;
                case "-":
                    sum = num1 - num2;
                    break;
                case "×":
                    sum = num1 * num2;
                    break;
                case "÷":
                    if (num2 != 0)
                        sum = num1 / num2;
                    else
                        messagebox.show("语法错误，除数不能为0，请重新输入...");
                    break;
                case "aⁿ":
                    sum = math.pow(num1, num2);
                    break;
                case "√￣":
                    if (num1 >= 0 && num2 != 0)
                        sum = math.pow(num1, 1 / num2);
                    else
                        messagebox.show("语法错误，根号内不能小于0且不能开0次方，请重新输入...");
                    break;
            }
            switch (pointbit.selectedindex) ///小数点控制    
            {
                case 0:
                    return convert.todouble(sum).tostring("f0");
                case 1:
                    return convert.todouble(sum).tostring("f1");
                case 2:
                    return convert.todouble(sum).tostring("f2");
                case 3:
                    return convert.todouble(sum).tostring("f3");
                case 4:
                    return sum.tostring();
            }
            return sum.tostring();
    }
    }
}