C#程序设计 输入三角形三边长,并计算的周长和面积

前台有五个TextBox,分别是FirstTxt,SecondTxt,ThridTxt(代表a,b,c三边长),areaTxt,aroundTxt(代表面积,周长),一个计算的Button.对输入进行了控制,对是否可形成三角形进行了控制,最终计算.计算三角形面积用的是海伦公式.下面是源码：using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Text.RegularExpressions;using System.Windows.Forms;namespace triangle{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        public double Alength;        public double Blength;        public double Clength;        private Regex reg = new Regex("^(0|[1-9][0-9]*)$");        //用于检测的正则表达式        //只能输入0或者非0开头的数字        private void Form1_Load(object sender, EventArgs e)        {            this.FirstTxt.Text = "1";            this.SecondTxt.Text = "1";            this.ThirdTxt.Text ="1";                     }        private bool TestTriangle(double a,double b,double c)        {//测试是否能形成三角形            double result1 = a + b;            double result2 = a + c;            double result3 = b + c;            if (result1>c&&result2>b&&result3>a)            {                return true;            }            else            {                return false;            }        }        private double CountArea(double a,double b,double c)        {//计算面积            double p = (a+b+c)/2;            double area = Math.Sqrt(p * (p - a) * (p - b) * (p - c));            return area;        }        private double CountAround(double a,double b,double c)        {//计算边长            return a + b + c;        }        private void count_Click(object sender, EventArgs e)        {                        if (reg.IsMatch(this.FirstTxt.Text)&®.IsMatch(this.SecondTxt.Text)&®.IsMatch(this.ThirdTxt.Text))            {                Alength = Double.Parse(this.FirstTxt.Text);                Blength = Double.Parse(this.SecondTxt.Text);                Clength = Double.Parse(this.ThirdTxt.Text);                if (TestTriangle(Alength, Blength, Clength))                {                    this.aroundtxt.Text = CountAround(Alength, Blength, Clength).ToString();                    this.areatxt.Text = CountArea(Alength, Blength, Clength).ToString();                }                else                {                    MessageBox.Show("当前不形成三角形!");                }            }            else            {                MessageBox.Show("请输入合法的边长值!");            }        }    }}