/// <summary>
        /// 行转列
        /// </summary>
        /// <param name="src_dt">需要转换的table</param>
        /// <param name="columnIndex">table中用来当作新列名的列的索引值（要求table此列的值不能重复）</param>
        /// <returns>table</returns>
        public static DataTable RowToColumn(DataTable src_dt, int columnIndex) //columnIndex 用来当作新列名的列
        {
            try
            {
                DataTable dt = new DataTable();
                dt.Columns.Add(src_dt.Columns[columnIndex].ColumnName);

                foreach (DataRow dr in src_dt.Rows)
                    dt.Columns.Add(dr[columnIndex].ToString());

                int n = src_dt.Columns.Count;
                for (int i = 0; i < n; i++)
                {
                    if (i == columnIndex) continue; //如果是被当作列名的列,则跳过

                    DataRow new_dr = dt.NewRow();
                    string columnName = src_dt.Columns[i].ColumnName;
                    new_dr[0] = columnName;

                    foreach (DataRow dr in src_dt.Rows)
                    {
                        string newColumnName = dr[columnIndex].ToString();
                        new_dr[newColumnName] = dr[columnName];
                    }

                    dt.Rows.Add(new_dr);
                }
                return dt;
            }
            catch (Exception e)
            {
                LogHelper.m_CreateErrorLogTxt(e.TargetSite.ToString(), e.Source, e.Message);
                return null;
            }
        }