/// 
        /// 滚动到某项        /// 
        ///         private void ScrollItem(Block sparent)        {            int count = richTextBox1.Document.ContentStart.GetOffsetToPosition(richTextBox1.Document.ContentEnd);//获取整个textbox中文本的高度            int s1 = richTextBox1.Document.ContentStart.GetOffsetToPosition(sparent.ContentEnd);//项block到文档起点的高度            int s2 = sparent.ContentEnd.GetOffsetToPosition(richTextBox1.Document.ContentEnd);//项block到文档结束点的高度             double h1 = (double)scHeight / count * s1;// (int)((scheight / 100) * s1);//滚动条高度平分，提取滚动条位置点            richTextBox1.ScrollToVerticalOffset(h1 - 60);        }        private void richTextBox1_ScrollChanged(object sender, ScrollChangedEventArgs e)        {            scHeight = e.ExtentHeight;        }