//添加自增长列 【ExcelTable读取Excel得到的数据表】

                        DataTable dt = ExcelTable.Clone();
                        DataColumn dc = new DataColumn("RowNum", typeof(int));
                        dc.AutoIncrement = true;
                        dc.AutoIncrementStep = 1;
                        dc.AllowDBNull = false;
                        dt.Columns.Add(dc);
                        DataTableReader dataTableReader = new DataTableReader(ExcelTable);
                        dt.Load(dataTableReader);