多联接LINQ和按年份和月份组

我有以下LINQ查询，我的目标是按年份和月份进行分组，并进行一些计算：我有一个ViewModel设置。我甚至不确定我的查询是否按预期工作，因为它不能编译。我得到这个错误多联接LINQ和按年份和月份组

System.NotSupportedException was unhandled by user code 
    HResult=-2146233067 
    Message=LINQ to Entities does not recognize the method 'System.Collections.Generic.IEnumerable`1[System.Int32] Range(Int32, Int32)' method, and this method cannot be translated into a store expression. 
    Source=EntityFramework

控制器代码

public ActionResult Summary(int? yr, int? mn, int? BkId) 
      { 
       var squery = SummaryYrMn(yr, mn, BkId); 
       return View(squery); 
      }  

    public IEnumerable SummaryYrMn() 
       { 
     var squery = 
     (from bk in db.Books 
     from year in Enumerable.Range(2010, DateTime.Today.Year) 
     from month in Enumerable.Range(1, 12) 
     let key = new { Year = year, Month = month } 

     //sold books 
     join tr in db.Transacts.Where(a => a.TransactTypeId==1 && a.Book.BookTypeId==1) on key 
     equals new{tr.TransactDate.Year, tr.TransactDate.Month} into s 

     //gifted books 
     join tr2 in db.Transacts.Where(a => a.TransactTypeId == 2 && a.Book.BookTypeId == 1) on key 
     equals new{tr2.TransactDate.Year, tr2.TransactDate.Month} into t 

     //gifted tracts books book type = tract 
     join tr3 in db.Transacts.Where(a => a.TransactTypeId == 2 && a.Book.BookTypeId == 2) on key 
     equals new { tr3.TransactDate.Year, tr3.TransactDate.Month } into u 

     select new SummaryViewModel 
     { 

     Year = year, 
     Month = month, 
     Gifted = (int?)t.Sum(c => c.TransactQty) ?? 0, 
     GSales = (int?)s.Sum(c => c.TransactQty) ?? 0, 
     GiftedTracts = (int?)u.Sum(c => c.TransactQty) ?? 0, 
     TotalGift = ((int?)t.Sum(c => c.Book.BookPrice))*((int?)s.Sum(c => c.TransactQty)??0), 
     TotalSale = ((int?)s.Sum(c => c.TransactPrice))*((int?)s.Sum(c => c.TransactQty)??0) 

     }); 

     return squery.AsEnumerable(); 
    }

来源

2016-04-02 Diin

如果不是[System.Linq.Enumerable]（https://msdn.microsoft.com/en-us/library/system.linq.enumerable（v = vs.100）.aspx）？尝试完全限定您的Enumerable.Range（）。 –

仍然无法处理您的建议。你会以不同的方式做到这一点吗？ – Diin

啊是的。我懂了。这是Linq的实体！是。为每个年份和月份创建一个变量，将Enumerable.Range赋值给它们。然后在你的linq中使用它们。 EF试图从你的linq生成sql，并且Enumerable.Range不是一个sql函数。那有意义吗？ –

开始尝试像这样的方法SummaryYrMn ...

var yrs = Enumerable.Range(2010, DateTime.Today.Year); 
var months = Enumerable.Range(1, 12);  
var squery = 
     (from bk in db.Books 
     from year in yrs 
     from month in months 
     let key = new { Year = year, Month = month } 
...

的Enumarable.Range（）正在被翻译成SQL Linq-to-Entities并不存在于sql上下文中。

来源

2016-04-03 11:47:26

多联接LINQ和按年份和月份组

回答

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