C#RichTextBox中回车不换行的做法

        private void richTextBoxSend_KeyDown(object sender, KeyEventArgs e)        {            //回车就送出消息            if (e.KeyCode == Keys.Enter)            {                buttonSend_Click(sender, e);            }        }        private void richTextBoxSend_KeyUp(object sender, KeyEventArgs e)        {            //防止输入框内文本回车换行            if (e.KeyCode == Keys.Enter)            richTextBoxSend.Text = "";        }