winform 给文本框加载内容的时候 始终让文本框的滚动条到底（允许显示多行Multiline=True）

  void textBox2_TextChanged(object sender, EventArgs e)
        {
            this.textBox2.SelectionStart = this.textBox2.TextLength;
            this.textBox2.SelectionLength = 0;
            this.textBox2.ScrollToCaret();
        }