C#のWinFormsで文字入力ダイアログボックスを作る

namespace TextInputDialog;

public partial class Form1 : Form
{
    static DialogResult ShowTextInputDialog(ref string text, string prompt = "プロンプト", string title = "タイトル" )
    {
        var frm = new Form
        {
            FormBorderStyle = FormBorderStyle.FixedDialog,
            ClientSize = new Size(300, 200),
            Text = title,
        };
        var lbl = new Label
        {
            Size = new Size(200, 60),
            Location = new Point(10, 30),
            Text = prompt,
        };
        frm.Controls.Add(lbl);
        var tb = new TextBox
        {
            Size = new Size(200, 60),
            Location = new Point(10, 90),
            Text = text,
        };
        frm.Controls.Add(tb);
        
        var okBtn = new Button
        {
            Size = new Size(60, 60),
            Location = new Point(60, 120),
            Text = "OK",
            DialogResult = DialogResult.OK,
        };
        frm.Controls.Add(okBtn);
        
        var calcelBtn = new Button
        {
            Size = new Size(50, 60),
            Location = new Point(120, 120),
            Text = "Cancel",
            DialogResult = DialogResult.Cancel,
        };
        frm.Controls.Add(calcelBtn);

        frm.AcceptButton = okBtn;
        frm.CancelButton = calcelBtn;

        var result = frm.ShowDialog();
        if (result == DialogResult.OK)
        {
            text = tb.Text;
        }

        return result;
    }
    public Form1()
    {
        InitializeComponent();

        string text = "元の文章";

        var btn = new Button
        {
            Width = 60,
            Height = 40,
            Location = new Point(50, 50),
            Text = "編集"
        };
        Controls.Add(btn);


        var lbl = new Label
        {
            Width = 200,
            Height = 40,
            Location = new Point(50, 120),
            Text = text,
        };
        Controls.Add(lbl);

        btn.Click += (s, e) =>
        {
            var result = ShowTextInputDialog(ref text);
            if (result == DialogResult.OK)
            {
                lbl.Text = text;
            }
        };
    }
}