c# 弹出三个按钮的对话框如何实现

        private void button1_Click(object sender, EventArgs e)
        {
            DialogResult dr;
            dr = MessageBox.Show("测试一下消息对话框", "测试测试", 
                 MessageBoxButtons.AbortRetryIgnore, MessageBoxIcon.Warning);
            if (dr==DialogResult.Abort)
            {
                MessageBox.Show("中止");
            }
            else if (dr==DialogResult .Retry)
            {
                 MessageBox.Show("重试");
            }
            else if (dr==DialogResult .Ignore)
            {
                MessageBox.Show("忽略");
            }
            else
            {
                MessageBox.Show("其他操作");
            }
        }