在富文本框中显示行号c#

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        richTextBox1.TextChanged += RichTextBox1_TextChanged;
    }

    private void RichTextBox1_TextChanged(object sender, EventArgs e)
    {
        string text = richTextBox1.Text;
        int lineCount = text.Split('\n').Length;
        string lineNumbers = "";

        for (int i = 1; i <= lineCount; i++)
        {
            lineNumbers += i.ToString() + "\n";
        }

        richTextBox1.Text = lineNumbers + text;
    }
}