帮我用C#语言，写一份计算器的WINDOWS窗口代码

在C#中创建一个简单的Windows窗体计算器程序，你可以使用Windows Forms库。下面是一个基本的示例，展示了一个简单的加减乘除按钮和两个输入框的计算器：

using System;
using System.Windows.Forms;

public partial class CalculatorForm : Form
{
    private double _firstNumber = 0;
    private double _secondNumber = 0;
    public CalculatorForm()
    {
        InitializeComponent();
    }

    // 按钮点击事件处理器
    private void buttonAdd_Click(object sender, EventArgs e)
    {
        if (_firstNumber != 0 || _secondNumber != 0)
        {
            _resultLabel.Text = String.Format("{0} + {1} = ", _firstNumber, _secondNumber);
            _firstNumber += Convert.ToDouble(_secondNumber);
            _secondNumber = 0;
        }
    }

    private void buttonSubtract_Click(object sender, EventArgs e)
    {
        if (_firstNumber != 0 || _secondNumber != 0)
        {
            _resultLabel.Text = String.Format("{0} - {1} = ", _firstNumber, _secondNumber);
            _firstNumber -= Convert.ToDouble(_secondNumber);
            _secondNumber = 0;
        }
    }

    private void buttonMultiply_Click(object sender, EventArgs e)
    {
        if (_firstNumber != 0 || _secondNumber != 0)
        {
            _resultLabel.Text = String.Format("{0} * {1} = ", _firstNumber, _secondNumber);
            _firstNumber *= Convert.ToDouble(_secondNumber);
            _secondNumber = 0;
        }
    }

    private void buttonDivide_Click(object sender, EventArgs e)
    {
        if (_firstNumber != 0 && _secondNumber != 0)
        {
            _resultLabel.Text = String.Format("{0} / {1} = ", _firstNumber, _secondNumber);
            _firstNumber /= Convert.ToDouble(_secondNumber);
            _secondNumber = 0;
        }
    }

    private void clearButton_Click(object sender, EventArgs e)
    {
        _firstNumber = 0;
        _secondNumber = 0;
        _resultLabel.Text = "";
    }

    // 将文本转换为数字并添加到输入框
    private void textBoxInput_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!char.IsDigit(e.KeyChar) && e.KeyChar != '.')
            return;
        
        var textBox = (TextBox)sender;
        var currentText = textBox.Text;
        textBox.Text = currentText + e.KeyChar.ToString();
    }

    private void textBoxInput_TextChanged(object sender, EventArgs e)
    {
        var textBox = (TextBox)sender;
        _firstNumber = Convert.ToDouble(textBox.Text);
    }

    private void resultLabel_TextChanged(object sender, EventArgs e)
    {

    }
}

// 主函数
class Program
{
    [STAThread]
    static void Main()
    {
        Application.Run(new CalculatorForm());
    }
}

这个例子中，我们创建了一个名为CalculatorForm的窗体，包含了四个操作按钮（加、减、乘、除），两个用于输入数字的文本框以及清除按钮。用户可以在文本框内输入数字，然后按相应的运算按钮计算结果。