BKI_DichVuMatDat.WinFormControls.format_data_header C# (CSharp) Method

        private static void format_data_header(DataTable dt)
        {
            foreach (DataColumn item in dt.Columns)
            {
                if (item.ColumnName.StartsWith("4"))
                {
                    var v_name_value = int.Parse(item.ColumnName.Trim());
                    var v_str_name = (new DateTime(1899, 12, 31).AddDays(v_name_value)).ToString("dd/MM/yyyy");
                    item.ColumnName = v_str_name;
                }
            }
        }