c# - ENTER キーを押して FORM を送信する

Question

OS: Windows Mobile 5 / Compact .NET Framework (Form.AcceptButton() は使用できません) ShowDialog()
でモーダル フォームを表示しています。Enterキーを押すとモーダルフォームを送信できるようにしたい。ENTER キーを押すと、KEYDOWN EVENT を取得できます。
他の解決策も高く評価されます。

public class Prompt
        {
            public static string AcceptTagPrice()
            {
                Form prompt = new Form();
                prompt.WindowState = System.Windows.Forms.FormWindowState.Maximized;
                prompt.TopMost = true;
                prompt.BackColor = System.Drawing.Color.White;
                prompt.KeyPreview = true;
                prompt.MaximizeBox = true;
                Label textLabel = new Label() { Text = "Enter Price", Left = 20, Top = 50, Width = 200, TextAlign = ContentAlignment.TopCenter, ForeColor = System.Drawing.Color.Green, Font = new System.Drawing.Font("Tahoma", 11F, System.Drawing.FontStyle.Bold) };
                TextBox textBox = new TextBox() { Left = 20, Top = 100, Size = new System.Drawing.Size(202, 31), BackColor = System.Drawing.Color.LightGray }; ;
                Button confirmation = new Button() { Text = "Submit", Left = 30, Top = 140, Size = new System.Drawing.Size(121, 33), BackColor = System.Drawing.Color.LightSkyBlue };
                confirmation.Click += (sender, e) => { bool k = IsValidPrice(textBox.Text); if (k) { prompt.Close(); } else { textBox.Focus(); } };
                prompt.KeyDown += new System.Windows.Forms.KeyEventHandler(Prompt.ModalForm_KeyDown);
                prompt.Controls.Add(confirmation);
                prompt.Controls.Add(textLabel);
                prompt.Controls.Add(textBox);
                textBox.Focus();
                prompt.Activate();
                prompt.ShowDialog();
                return textBox.Text.ToString().Trim();
            }

            public static bool IsValidPrice(string price)
            {
                if (!Regex.IsMatch(price, @"^[0-9]\d*(\.\d+)?$"))
                {
                    MessageBox.Show("Please enter a valid price", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation, MessageBoxDefaultButton.Button1);
                    return false;
                }
                else
                {
                    return true;
                }
            }

            private static void ModalForm_KeyDown(object sender, KeyEventArgs e)
            {
                if (e.KeyData == Keys.Enter)
                {
                      Messagebox.Show("Enter Key Pressed");
                    // BUT DUNNO HOW TO TRIGGER CONFIRMATION BUTTON CLICK EVENT 
                }
            }
        }