Question

我在循环中为类对象赋值，显然我因日期空值而得到错误。

我的问题是我可以使用LINQ检查对象内的值

kubectl get pods

我需要检查三个日期变量是否为null。如果为null，那么我需要忽略它而不是将它们转换为日期

Answer 1

如果要从查询中删除项目，可以添加

.Where(item => item.ProgressDate != null)

查询。

如果您不想解析null的日期但仍使用可以使用的项目

ProgressDate = item.ProgressDate != null ? Convert.ToDateTime(item.ProgressDate) :null

在对象创建中

Answer 2

通过使用Convert.ToDateTime()函数，我假设您的数据属于string类型。使用?:运算符检查它是否为空。如果是，则使用默认的DateTime值，否则转换。

var defaultDate = DateTime.MinValue;
EnrolmentList.AddRange(_query.Select(item => new EnrolmentEntity
    {
        PeopleUnitsID = item.PeopleUnitsID,
        PersonCode = item.PersonCode,
        UnitType = item.UnitType,
        ProgressCode = item.ProgressCode,
        ProgressStatus = item.ProgressStatus,
        ProgressDate = item.ProgressDate == null ? defaultDate : Convert.ToDateTime(item.ProgressDate),
        UnitInstanceID = item.UnitInstanceID,
        UnitInstanceOccurrenceID = item.UnitInstanceOccurrenceID,
        CourseCode = item.CourseCode,
        OwningOrganisation = item.OwningOrganisation,
        CalendarOccurrenceCode = item.CalendarOccurrenceCode,
        FES_Start_Date = item.FES_Start_Date == null ? defaultDate : Convert.ToDateTime(item.FES_Start_Date),
        AimStartDate = item.AimStartDate == null ? defaultDate : Convert.ToDateTime(item.AimStartDate)
    }));

此外，您可以将foreach + Add替换为.Select + AddRange

Answer 3

假设您的3个输入日期是DateTime的类型？如果为null，您想要默认（DateTime），您可以使用GetValueOrDefault()

foreach (var item in _query)
        {
            EnrolmentList.Add(new EnrolmentEntity
            {
                PeopleUnitsID = item.PeopleUnitsID,
                PersonCode = item.PersonCode,
                UnitType = item.UnitType,
                ProgressCode = item.ProgressCode,
                ProgressStatus = item.ProgressStatus,
                ProgressDate = item.ProgressDate.GetValueOrDefault(),
                UnitInstanceID = item.UnitInstanceID,
                UnitInstanceOccurrenceID = item.UnitInstanceOccurrenceID,
                CourseCode = item.CourseCode,
                OwningOrganisation = item.OwningOrganisation,
                CalendarOccurrenceCode = item.CalendarOccurrenceCode,
                FES_Start_Date = item.FES_Start_Date.GetValueOrDefault(),
                AimStartDate = item.AimStartDate.GetValueOrDefault()
            });
        }

Answer 4

我将日期对话的字符串null检查为;

  public class EnrolmentEntity
{

    public DateTime? ProgressDate { get; set; }

    public DateTime? FES_Start_Date { get; set; }

    public DateTime? AimStartDate { get; set; }
}

//

 public class Enrolments
 {    
    [XmlElement("PROGRESS_STATUS")]
    public string ProgressStatus { get; set; }

    [XmlElement("PROGRESS_DATE")]
    public string ProgressDate { get; set; }

    [XmlElement("FES_START_DATE")]
    public string FES_Start_Date  { get; set; }

    [XmlElement("AIM_START")]
    public string AimStartDate { get; set; } 

 }

//

foreach (var item in _query)
   {
     EnrolmentList.Add(new EnrolmentEntity
      {
        PeopleUnitsID = item.PeopleUnitsID,
        PersonCode = item.PersonCode,
        UnitType = item.UnitType,
        ProgressCode = item.ProgressCode,
        ProgressStatus = item.ProgressStatus,
        ProgressDate = string.IsNullOrEmpty(item.ProgressDate) ? (DateTime?)null : DateTime.Parse(item.ProgressDate), 
        UnitInstanceID = item.UnitInstanceID,
        UnitInstanceOccurrenceID = item.UnitInstanceOccurrenceID,
        CourseCode = item.CourseCode,
        OwningOrganisation = item.OwningOrganisation,
        CalendarOccurrenceCode = item.CalendarOccurrenceCode,
        FES_Start_Date = string.IsNullOrEmpty(item.FES_Start_Date) ? (DateTime?)null : DateTime.Parse(item.FES_Start_Date), 
        AimStartDate = string.IsNullOrEmpty(item.AimStartDate)? (DateTime?)null :DateTime.Parse(item.AimStartDate)  
 });

检查null条件以将字符串日期转换为对象内的DateTime

4 个答案: