C#在RichTexBox里选中某一行的字符

 

 /// <summary>
        /// 获取richTexBox行的字符长度
        /// </summary>
        /// <param name="rowNun"></param>
        /// <returns></returns>
        private Int32 GetLineCharacterCount(int rowNun)
        {
            String[] lines = log_textbox.Lines;
            if (rowNun < 0 || rowNun > lines.Length - 1)
            {
                return -1;
            }
            return lines[rowNun].Length;
        }

private void log_textbox_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            Int32 lineNum = log_textbox.GetLineFromCharIndex(log_textbox.SelectionStart);//获取首行的行号
            Int32 lineCharCount = GetLineCharacterCount(lineNum);//
            if (lineCharCount < 0)
            {
                MessageBox.Show("文本框里没有数据！", "提示");
                return;
            }

            int selectStart = log_textbox.GetFirstCharIndexFromLine(lineNum);
            log_textbox.Select(selectStart, lineCharCount);

        }