Question

我有一个表（我正在使用实体模型）并使用LINQ查询过滤该表，该查询工作正常。现在我想根据日期数组过滤记录。我无法在日期数组上实现IN子句

filteredList = leadsNewAndScheduled.Where(lead =>  
              (LeadTypeIDs.Contains(lead.TYPE_ID.ToString()) ||
              LeadTypeIDs == string.Empty) &&
              (priorityIDs.Contains(lead.PRIORITY_ID.ToString()) ||
              priorityIDs == string.Empty) &&
              (((lead.EXPIRED_ON <= dateExpiry ||
              Convert.ToDateTime(lead.EXPIRED_ON) == DateTime.Today.Date) &&
              lead.STATUS_ID == (int)Enumerations.LeadStatus.New) ||
              lead.STATUS_ID == (int)Enumerations.LeadStatus.Active) &&
              (lead.START_TIME IN (arrAppointmentDates))
            ).ToList();

我希望你的帮助如下

(lead.START_TIME IN (arrAppointmentDates))

提前致谢。

Answer 1

使用Predicate Builder

编写没有日期条件的查询，如

var query = leadsNewAndScheduled.Where(lead =>  
              (LeadTypeIDs.Contains(lead.TYPE_ID.ToString()) ||
              LeadTypeIDs == string.Empty) && ....

然后写

  var predicate = PredicateBuilder.False<Lead>();

  foreach (DateTime date in dates)
  {
    DateTime temp = date;
    predicate = predicate.Or (p => p.START_TIME == temp);
  }

  var result = query.Where(predicate).ToList(); // Don't call ToList() earlier

但是请注意，如果您正在使用Entity Framework，则需要在实体集上调用AsExpandable（），然后才能在其上应用谓词：

return objectContext.Products.AsExpandable().Where (predicate);

Answer 2

我在声明日期列表然后在LINQ查询中应用contains子句时解决了这个问题。

示例：

//list of dates.
List<DateTime> arrAppointmentDates;

//change in query
arrAppointmentDates.Contains(Convert.ToDateTime(lead.START_TIME).Date)

LINQ查询记录基于日期数组

2 个答案: