回車鍵觸發某個OK按鈕的事件，Esc鍵是關閉視窗

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
        {
            if (keyData == Keys.Enter)
            {
                if (btnOK.Enabled)
                {
                    btnOK_Click(btnOK, new EventArgs());
                }
                return true;
            }

            if (keyData == Keys.Escape)
            {
                this.Close();
                return true;
            }

            return base.ProcessCmdKey(ref msg, keyData);
        }