c# - Linq to Entity 生日比较

Question

我需要使用 Linq to Entities 创建一个查询，其中生日必须在 2 天前和接下来的 30 天内。

以下不返回任何内容:

DateTime twoDaysAgo = DateTime.Now.AddDays(-2);
int twoDaysAgoDay = twoDaysAgo.Day;
int twoDaysAgoMonth = twoDaysAgo.Month;
DateTime MonthAway = DateTime.Now.AddDays(30);
int monthAwayDay = MonthAway.Day;
int monthAwayMonth = MonthAway.Month;
var bdays = from p in db.Staffs where EntityFunctions.TruncateTime(p.BirthDate) > EntityFunctions.TruncateTime(twoDaysAgo) &&
                     EntityFunctions.TruncateTime(p.BirthDate) < EntityFunctions.TruncateTime(MonthAway)
                    orderby p.BirthDate select p;
return bdays;

我遇到的问题是，如果生日从 11 月 3 日降到 12 月 5 日，我需要一些东西，它应该返回它。它失败的原因是生日包括年份。但是，当我使用类似的东西时:

p.BirthDate.Value.Month 

我收到了 Linq to Entities 不支持的错误。如有任何帮助，我们将不胜感激。

Answer 1

年度总结独立解决方案:

void Main()
{
    var birthdays = new List<DateTime>();
    birthdays.Add(new DateTime(2013, 11, 08));
    birthdays.Add(new DateTime(2012, 05, 05));
    birthdays.Add(new DateTime(2014, 05, 05));
    birthdays.Add(new DateTime(2005, 11, 08));
    birthdays.Add(new DateTime(2004, 12, 31));


    foreach(var date in birthdays.Where(x => x.IsWithinRange(twoDaysAgo, MonthAway))){
      Console.WriteLine(date);
    }           
}

public static class Extensions {
    public static bool IsWithinRange(this DateTime @this, DateTime lower, DateTime upper){
        if(lower.DayOfYear > upper.DayOfYear){
            return (@this.DayOfYear > lower.DayOfYear || @this.DayOfYear < upper.DayOfYear);
        } 

        return (@this.DayOfYear > lower.DayOfYear && @this.DayOfYear < upper.DayOfYear);
    }
}

输出方式

DateTime twoDaysAgo = DateTime.Now.AddDays(-2);
DateTime MonthAway = DateTime.Now.AddDays(30);

8/11/2013 0:00:00
8/11/2005 0:00:00

输出方式

DateTime twoDaysAgo = new DateTime(2012, 12, 25);
DateTime MonthAway = new DateTime(2013, 01, 05);

31/12/2004 0:00:00