LINQ 2 Entities，如何在linq查询中检查DateTime.HasValue [英] LINQ 2 Entities , howto check DateTime.HasValue within the linq query

问题描述

我有这个方法，该方法应该从称为ENTRY的表(& EntitySet)中获取最新消息的发布

I have this method that is supposed to get the latest messages posted, from the Table (& EntitySet) called ENTRY

////方法获取天"作为参数，用于新的TimeSpan(days，0,0,0); !!

///method gets "days" as parameter, used in new TimeSpan(days,0,0,0);!!

using (Entities db = new Entities())
    {
        var entries = from ent in db.ENTRY
                      where ent.DATECREATE.Value > DateTime.Today.Subtract(new TimeSpan(days, 0, 0, 0))
                      select new ForumEntryGridView()
                      {
                          id = ent.id,
                          baslik = ent.header,
                          tarih = ent.entrydate.Value,
                          membername = ent.Member.ToString()
                      };
        return entries.ToList<ForumEntryGridView>();
    }

这里DATECREATED在数据库中为空.我无法在此查询中放置如果" ...以任何方式进行检查吗?提前谢谢

Here the DATECREATED is Nullable in the database. I cant place "if"s in this query ... any way to check for that? Thx in advance

推荐答案

在DATECREATED是null的情况下您要做什么?

What do you want to do in case DATECREATED is null?

如果您只想忽略这些记录，请使用其他条件(或where子句):

If you just want to ignore these records use an additional condition(or where clause):

var entries = from ent in db.ENTRY
              where ent.DATECREATED.HasValue && ent.DATECREATED.Value > ...

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