验证排除周末的员工请假天数统计逻辑，修复求和结果错误

问题说明 #

需要按年月维度统计所有员工的请假总天数，统计规则要求排除周末，但当前代码的计算结果存在错误。

现有代码 #

核心计算方法 #

public double CalculateLeaveDaysForPeriod(List<EmployeeInfoDto> staffMembers, DateTime periodStart, DateTime periodEnd)
{
    double totalLeaveDays = 0;

    foreach (var staffMember in staffMembers)
    {
        foreach (var leaveRequest in staffMember.LeaveRequests)
        {
            DateTime leaveStartDate = leaveRequest.StartDate;
            DateTime leaveEndDate = leaveRequest.EndDate;

            DateTime validStartDate = leaveStartDate > periodStart ? leaveStartDate : periodStart;
            DateTime validEndDate = leaveEndDate < periodEnd ? leaveEndDate : periodEnd;

            if (validStartDate < validEndDate)
            {
                for (DateTime currentDay = validStartDate; currentDay <= validEndDate; currentDay = currentDay.AddDays(1))
                {
                    if (currentDay.DayOfWeek != DayOfWeek.Saturday && currentDay.DayOfWeek != DayOfWeek.Sunday)
                    {
                        totalLeaveDays++;
                    }
                }
            }
        }
    }
    return totalLeaveDays;
}

年月维度统计方法 #

public double GetLeaveDaysForCurrentMonth(List<EmployeeInfoDto> employees)
{
    var currentDate = DateTime.Now;
    var startOfMonth = new DateTime(currentDate.Year, currentDate.Month, 1); 
    var endOfMonth = startOfMonth.AddMonths(1).AddDays(-1); 

    return GetLeaveDaysForTimePeriod(employees, startOfMonth, endOfMonth);
}

public double GetLeaveDaysForCurrentYear(List<EmployeeInfoDto> employees)
{
    var currentDate = DateTime.Now;
    var startOfYear = new DateTime(currentDate.Year, 1, 1); 
    var endOfYear = new DateTime(currentDate.Year, 12, 31); 

    return GetLeaveDaysForTimePeriod(employees, startOfYear, endOfYear);
} 

员工请假数据示例（JSON） #

[
  {
    "leaveRequests": [
      {
        "startDate": "2025-01-07T23:00:00Z",
        "endDate": "2025-01-09T23:00:00Z"
      }
    ]
  },
  {
    "leaveRequests": [
      {
        "startDate": "2025-01-05T23:00:00Z",
        "endDate": "2025-01-17T23:00:00Z"
      }
    ]
  },
  {
    "leaveRequests": [
      {
        "startDate": "2025-01-08T23:00:00Z",
        "endDate": "2025-01-23T23:00:00Z"
      }
    ]
  }
]

错误原因分析 #

1. 方法调用不匹配：GetLeaveDaysForCurrentMonth和GetLeaveDaysForCurrentYear调用了不存在的GetLeaveDaysForTimePeriod方法，实际核心方法是CalculateLeaveDaysForPeriod，直接导致编译错误或执行异常。
2. 时区与时间干扰：JSON中的日期为UTC格式（带Z后缀），但代码直接用DateTime处理未做时区转换，且保留时间部分，会导致日期边界判断错误（例如2025-01-07T23:00:00Z转换为本地时间可能变为1月8日）。
3. 日期范围判断逻辑缺陷：if (validStartDate < validEndDate)会跳过请假起始与结束为同一天的场景，导致当天请假天数未被统计。
4. 循环边界误差：使用带时间的DateTime进行循环遍历，可能因时间部分导致重复统计或漏统计。

修复后的代码 #

修正后的核心计算方法 #

public double CalculateLeaveDaysForPeriod(List<EmployeeInfoDto> staffMembers, DateTime periodStart, DateTime periodEnd)
{
    double totalLeaveDays = 0;
    // 统一转换为UTC时间，对齐JSON数据的时区
    DateTime utcPeriodStart = periodStart.ToUniversalTime();
    DateTime utcPeriodEnd = periodEnd.ToUniversalTime();

    foreach (var staffMember in staffMembers)
    {
        foreach (var leaveRequest in staffMember.LeaveRequests)
        {
            // 将请假日期转换为UTC时间
            DateTime leaveStartUtc = leaveRequest.StartDate.ToUniversalTime();
            DateTime leaveEndUtc = leaveRequest.EndDate.ToUniversalTime();

            // 使用DateOnly忽略时间部分，专注日期计算
            DateOnly leaveStart = DateOnly.FromDateTime(leaveStartUtc);
            DateOnly leaveEnd = DateOnly.FromDateTime(leaveEndUtc);
            DateOnly periodStartDate = DateOnly.FromDateTime(utcPeriodStart);
            DateOnly periodEndDate = DateOnly.FromDateTime(utcPeriodEnd);

            // 确定有效统计范围
            DateOnly actualStart = leaveStart > periodStartDate ? leaveStart : periodStartDate;
            DateOnly actualEnd = leaveEnd < periodEndDate ? leaveEnd : periodEndDate;

            // 覆盖当天请假的场景
            if (actualStart <= actualEnd)
            {
                for (DateOnly currentDay = actualStart; currentDay <= actualEnd; currentDay = currentDay.AddDays(1))
                {
                    if (currentDay.DayOfWeek != DayOfWeek.Saturday && currentDay.DayOfWeek != DayOfWeek.Sunday)
                    {
                        totalLeaveDays++;
                    }
                }
            }
        }
    }
    return totalLeaveDays;
}

修正后的年月统计方法 #

public double GetLeaveDaysForCurrentMonth(List<EmployeeInfoDto> employees)
{
    var currentDate = DateTime.Now;
    var startOfMonth = new DateTime(currentDate.Year, currentDate.Month, 1); 
    var endOfMonth = startOfMonth.AddMonths(1).AddDays(-1); 

    return CalculateLeaveDaysForPeriod(employees, startOfMonth, endOfMonth);
}

public double GetLeaveDaysForCurrentYear(List<EmployeeInfoDto> employees)
{
    var currentDate = DateTime.Now;
    var startOfYear = new DateTime(currentDate.Year, 1, 1); 
    var endOfYear = new DateTime(currentDate.Year, 12, 31); 

    return CalculateLeaveDaysForPeriod(employees, startOfYear, endOfYear);
}

修复要点说明 #

• 统一使用UTC时间处理，解决JSON数据与本地时间的时区偏差问题；
• 采用DateOnly类型（.NET 6及以上版本支持），彻底消除时间部分对日期统计的干扰；
• 修正方法调用名称，确保调用正确的核心计算逻辑；
• 调整日期范围判断条件为actualStart <= actualEnd，覆盖当天请假的统计场景；
• 循环遍历使用DateOnly，保证日期判断的准确性。

内容的提问来源于stack exchange，提问作者Kafkaa