C#根据期间编码PeriodId获取期间的日期范围

/// <summary>
/// 获取会计期的日期范围，如：periodId=202308，返回：2023-08-01,2023-08-31
/// </summary>
/// <param name="periodId"></param>
/// <param name="begin"></param>
/// <param name="end"></param>
public static void GetPeriodDateRange(string periodId, ref DateTime begin, ref DateTime end)
{
    //202308
    int year = Int32.Parse(periodId.GetLeft(4));
    int month = Int32.Parse(periodId.GetRight(2));
    int day = DateTime.DaysInMonth(year, month);
    begin = new DateTime(year, month, 1);
    end = new DateTime(year, month, day);
}

 DateTime startDate = DateTime.MinValue;
 DateTime endDate = DateTime.MinValue;
 var PeriodId = txt_PeriodId.EditValue.ToStringEx();
 PeriodHelper.GetPeriodDateRange(PeriodId, ref startDate, ref endDate);
 txtDateFrom.DateTime = startDate;
 txtDateTo.DateTime = endDate;