private void richTextBox2_TextChanged(object sender, EventArgs e)
        {
    
    
            /* 滚条设置在最下方 */
            this.richTextBox2.Focus();                                //获取焦点
            this.richTextBox2.Select(this.richTextBox1.TextLength, 0);//光标定位到文本最后
            this.richTextBox2.ScrollToCaret();                        //滚动到光标处
        }