temperature translate tool

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

namespace WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            float x;
            double y;
            try
            {
                x = Single.Parse(textBox1.Text);
                y = getValue(x);
                label2.Text = "" + y;
            }
            catch (MyException ee)
            {
                label2.Text = ee.Message;
            }
            catch (FormatException ee)
            {
                label2.Text = ee.Message;
            }
        }
        private double getValue(float x)
        {
            double y;
            if (x < -273.15f) throw new MyException();
            y = x * 1.8f + 32;
            return y;
        }

        class MyException : ApplicationException
        {
            public MyException()
                : base("out of temperature range")
            { }
        }
        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }  
    }
}

/*
*temperature translate tool 
*by 2018/09/18
*hekies
*/