C# 根据日、周和月筛选数据

我想过滤今天、每周和每月的数据

var data = new DashboardViewModel()
           {
               Today = new State() { Download = db.Download.Where(x => x.Time == DateTime.Today).Count(), Visit = db.Visit.Where(x => x.Time == DateTime.Today).Count() },
               Week = new State() { Download = db.Download.Where(x => x.Time.DayOfYear <= Day && x.Time.DayOfYear >= Day - 7).Count(), Visit = db.Visit.Where(x => x.Time.DayOfYear <= Day && x.Time.DayOfYear >= Day - 7).Count() },
               Month = new State() { Download = db.Download.Where(x => x.Time.DayOfYear <= Day && x.Time.DayOfYear >= Day - 30).Count(), Visit = db.Visit.Where(x => x.Time.DayOfYear <= Day && x.Time.DayOfYear >= Day - 30).Count() },
               Total = new State() { Download=db.Download.Count(),Visit=db.Visit.Count()}
           };

var data=新的仪表板视图模型（）
{
Today=new State（）{Download=db.Download.Where（x=>x.Time==DateTime.Today）.Count（），Visit=db.Visit.Where（x=>x.Time==DateTime.Today）.Count（），
Week=new State（）{Download=db.Download.Where（x=>x.Time.DayOfYear=Day-7）.Count（），Visit=db.Visit.Where（x=>x.Time.DayOfYear=Day-7），
Month=new State（）{Download=db.Download.Where（x=>x.Time.DayOfYear=Day-30）.Count（），Visit=db.Visit.Where（x=>x.Time.DayOfYear=Day-30），
总计=新状态（）{Download=db.Download.Count（），Visit=db.Visit.Count（）}
};

它给出了错误：

LINQ to实体中不支持指定的类型成员“DayOfYear”

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如何解决此错误，或者是否有其他更好的方法来解决此问题？

问题是，当LINQ to Entities解析lambda表达式并将其转换为SQL时，它不知道什么是“DayOfYear”，以及它如何映射到有效的SQL。这就是（在v6之前的EF中）的用武之地，它允许您在LINQ中使用日期操纵函数来处理实体。例如，要按周筛选，可以使用：

Week = new State() { 
    Download = db.Download.Where(x => DbFunctions.DiffDays(DbFunctions.TruncateTime(x.Time), Day) <= 7).Count(), 
    Visit = db.Visit.Where(x => DbFunctions.DiffDays(DbFunctions.TruncateTime(x.Time), Day) <= 7).Count() }

Week=newstate（）{
Download=db.Download.Where（x=>DbFunctions.DiffDays（DbFunctions.TruncateTime（x.Time），Day）DbFunctions.DiffDays（DbFunctions.TruncateTime（x.Time），Day）请参见：

var ruleDate = Convert.ToDateTime(rule.data).Date;
return jobdescriptions.Where(j.Deadline.Year == ruleDate.Year 
                       && j j.Deadline.Month == ruleDate.Month 
                       && j.Deadline.Day == ruleDate.Day);