需要两个不同的文本框，以仅允许数字0-9和1小数位

好的，我所有的代码都可以正常工作了。但是我无法在textbox1和textbox3中输入小数位。我也只希望能够在这些文本框中输入数字0-9。到目前为止，到目前为止，一切对我都有效，但是当我输入“。”时。我得到一个错误。我认为，一旦我能够输入小数，就可以确定我也可以添加负号。我想我需要正确使用e.KeyChar吗？

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 TemperatureConversion
{
    /// <summary>
    /// A program that turns Fahrenheit to Celsius.
    /// </summary>

    public partial class TemperatureConversionGYG : Form
    {
        // Varable for the calculatedCelsius output in textbox2
        float calculatedCelsius;

        // Varable for the Fahrenheit entered in textbox1.
        float originalFahrenheit;

        // Varable for the Celsius entered in textbox3.
        float originalCelsius;

        // Varable for the calculated fharenheit when user enters celsius to turn into fharenheit.
        float calculatedTemperatureFahrenheit;

        public TemperatureConversionGYG()
        {
            InitializeComponent();
        }

        public void button1_Click(object sender, EventArgs e)
        {
            // When this button is clicked it will use the number the user inputs in textbox1(FahrenheitNumber) to 
            // calculate the degree celsius and output it in textbox2. 
            calculatedCelsius = (originalFahrenheit - 32) / 9 * 5; 

            //Code here to send the calculatedCelsius to textbox2
            textBox2.Text = calculatedCelsius.ToString();
        }

        public void textBox1_TextChanged(object sender, EventArgs e)
        {
            // originalFahrenheit that the program will read and convert it to a float when user inputs a number.
            originalFahrenheit = Convert.ToInt32(textBox1.Text);
        }

        public void textBox2_TextChanged(object sender, EventArgs e)
        {
            // Need this box to accept 1 decimal. example 7.2, 55.5, 99 
        }

        private void Twitter_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            // Navigate to a URL.
            System.Diagnostics.Process.Start("https://twitter.com/GYGamers");
        }

        private void textBox3_TextChanged(object sender, EventArgs e)
        {
            // originalCelsius that the program will read and convert it to a float when user inputs a number.
            originalCelsius = Convert.ToInt32(textBox3.Text);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            // This turns origianlCelsius to Fahrenheit.
            calculatedTemperatureFahrenheit = (originalCelsius * 9) / 5 + 32;

            //Code here to send the calculatedTemperatureFahrenheit to textbox4
            textBox4.Text = calculatedTemperatureFahrenheit.ToString();
        }

        private void textBox4_TextChanged(object sender, EventArgs e)
        {
            // Need this box to  accept  1 decimal. example 7.2, 55.5, 99 
        }
    }
}