实体中存在投放问题. [英] Having casting problem in Entity.

问题描述

  var  itemOne = 来自 n 其中 n.CodeNo ==代码
              选择 n.CodeNo;
 var  itemTwo =来自 db中的来自 db.地址
              其中(itemOne.Contains(p.AddCode))
              选择 p; 

运行时出现此错误-
LINQ to Entities无法识别方法``Boolean Contains [Decimal](System.Linq.IQueryable`1 [System.Decimal]，System.Decimal)''方法，并且该方法无法转换为商店表达式. class ="h2_lin">解决方案

var itemOne是Decimal.您说，在查询itemOne 的末尾，它应该选择n.CodeNo.因此，您选择的是Decimal，而不是TimeTable (我想您实际上要选择).
在itemTwo 查询中，您要查找itemOne (一个 TimeTable Decimal.Contains(AddCode).)，一个Decimal 没有Contains Function，所以它将永远找不到它！

  var  itemOne = 来自 n 在 db.TimeTable中
              其中 n.CodeNo ==代码
              选择 n； // 不是n.CodeNo！
 var  itemTwo =来自 db中的来自 db.地址
              其中(itemOne.Contains(p.AddCode))
              选择 p; 

我认为这将解决您的问题.为了确保itemOne 和itemTwo 的类型悬停在其前面的var 关键字上.
希望对您有所帮助！ :)

var itemOne = from n in db.TimeTable
              where n.CodeNo == code
              select n.CodeNo;
var itemTwo = from p in db.Address
              where (itemOne.Contains(p.AddCode))
              select p;

Got this error when run-
LINQ to Entities does not recognize the method ''Boolean Contains[Decimal](System.Linq.IQueryable`1[System.Decimal], System.Decimal)'' method, and this method cannot be translated into a store expression.

解决方案

var itemOne is a Decimal. You say, at the end of the query for itemOne that it should select n.CodeNo. So you are selecting a Decimal, not a TimeTable (which I think you want to actually select).
In the itemTwo query you want to look where itemOne (a TimeTable Decimal.Contains(AddCode). Well, a Decimal does not have a Contains Function, so it will never find it!

var itemOne = from n in db.TimeTable
              where n.CodeNo == code
              select n; // Not the n.CodeNo!
var itemTwo = from p in db.Address
              where (itemOne.Contains(p.AddCode))
              select p;

I think that will solve your problem. To make sure what the type of itemOne and itemTwo are hoover over the var keyword in front of it.
Hope that helps! :)

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