用C#窗体应用程序计算圆周

using System;
using System.Drawing;
using System.Windows.Forms;

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

        private void buttonCalculate_Click(object sender, EventArgs e)
        {
            double radius = double.Parse(textBoxRadius.Text);
            double circumference = 2 * Math.PI * radius;
            double area = Math.PI * radius * radius;

            labelCircumference.Text = "周长: " + circumference.ToString("F2");
            labelArea.Text = "面积: " + area.ToString("F2");
        }
    }
}