C # RichTextBox scroll bar to scroll to the last line

    //让文本框获取焦点，不过注释这行也能达到效果
    //richTextBoxReceive.Focus();
    //设置光标的位置到文本尾   
    richTextBoxReceive.Select(richTextBoxReceive.TextLength, 0);
    //滚动到控件光标处   
    richTextBoxReceive.ScrollToCaret();
    richTextBoxReceive.AppendText(text);