无法使用。由于< AnonymousType&gt [英] Can't use .Union with Linq due to <AnonymousType>

问题描述

我遇到了这个问题。希望我会得到一些帮助。
这是要点。
我必须使用该SQL请求填写我的DataGridView：

  SELECT LOT.NumLot，EtatLot，NomEmploye FROM LOT 
 JOIN AFFECTATION_LOT on LOT.NumLot = AFFECTATION_LOT.NumLot 
 JOIN EMPLOYE on AFFECTATION_LOT.IdEmploye = EMPLOYE.IdEmploye 
 WHERE EtatLot ='Libéré'或EtatLot ='Suspendu'或EtatLot ='Démarré'
 UNION 
 SELECT NumLot，EtatLot，null FROM LOT 
 WHERE EtatLot ='Démarré'
  

首先我在第二个SELECT中使用了null值，因为UNION需要有第一个SELECT的3个参数，表中没有NomEmploye数据。
无论如何，请求在SQL中运行良好。
但是当我尝试在LINQ中使用它时

  string test =null; 
 var listeLotControle =（from x in entBoum.LOT 
 join in in entBoum.AFFECTATION_LOT on x.NumLot equals aff.NumLot 
 join emp in entBoum.EMPLOYE on aff.IdEmploye equals emp.IdEmploye 
其中x.EtatLot.Contains（Libéré）|| x.EtatLot.Contains（Suspendu）|| x.EtatLot.Contains（Démarré）
选择新的{x.NumLot，联合
（来自x in entBoum.LOT 
其中x.EtatLot.Contains（Démarré）
选择新的{x.NumLot，x。 EtatLot，test}）; 
 dataGridViewAffectationLotControleur.DataSource = listeLotControle.ToList（）; 
  

我在Visual Studio中有3个错误，我不太明白。

 错误1参数实例：无法将System.Linq.IQueryable AnonymousType＃1>转换为System.Linq.ParallelQuery< AnonymousType＃ 2>'
错误2'System.Linq.IQueryable< AnonymousType＃1>'不包含'Union'的定义，并且最佳重载扩展方法'System.Linq.ParallelEnumerable.Union< TSource> （System.Linq.ParallelQuery< TSource> System.Collections.Generic.IEnumerable< TSource>）'
错误3方法'System.Linq.Enumerable.ToList< TSource>的类型参数（System.Collections.Generic.IEnumerable< TSource>）'不能从使用中推断出来。尝试显式指定类型参数。 
  

如我所见，问题是由于< AnonymousType> ....但是现在不能帮助我。
我也尝试过这样的方式使其工作。

  IQueryable listeLotControle; 
 string test =null; 
 listeLotControle =（从x在entBoum.LOT 
中加入aff中的entBoum.AFFECTATION_LOT x.NumLot等于aff.NumLot 
在entBoum.EMPLOYE中加入emp对于aff.IdEmploye等于emp.IdEmploye 
其中x.EtatLot.Contains（Libéré）|| x.EtatLot.Contains（Suspendu）|| x.EtatLot.Contains（Démarré）
选择新的{x.NumLot，x .EtatLot，emp.NomEmploye}）。Union 
（from x in entBoum.LOT 
其中x.EtatLot.Contains（Démarré）
选择新的{x.NumLot，x.EtatLot ，test}）; 
 dataGridViewAffectationLotControleur.DataSource = listeLotControle.ToList（）; 
  

但是我有相同的错误加上一个

 错误4'System.Linq.IQueryable'不包含'ToList'的定义，并且没有扩展方法'ToList'接受类型为'System.Linq.IQueryable的第一个参数'被发现（使用指令或程序集参考是否缺少？）
  

我可能需要使用，但哪一个？ （我确切地说，我已经使用使用System.Linq; ）

最后我尝试了最后一个方法。

  string test =null; 
 var listeLotControle = from x in entBoum.LOT 
在x.NumLot上的entBoum.AFFECTATION_LOT中加入aff等于aff.NumLot 
在entBoum.EMPLOYE中加入emp对于aff.IdEmploye等于emp.IdEmploye 
其中x.EtatLot.Contains（Libéré）|| x.EtatLot.Contains（Suspendu）|| x.EtatLot.Contains（Démarré）
选择新的{x.NumLot，x.EtatLot，emp.NomEmploye}; 
 var listeLotControle2 = from in in EntBoum.LOT 
其中x.EtatLot.Contains（Démarré）
选择新的{x.NumLot，x.EtatLot，test}; 
 var union = listeLotControle.Union（listeLotControle2）; 
 dataGridViewAffectationLotControleur.DataSource = listeLotControle2.ToList（）; 
  

但我仍然有这些错误

 错误1'System.Linq.IQueryable< AnonymousType＃1>'不包含'Union'的定义，并且最佳重载扩展方法'System.Linq.ParallelEnumerable.Union< TSource> （System.Linq.ParallelQuery< TSource>，System.Collections.Generic.IEnumerable< TSource>）'包含无效的参数
错误2参数实例：无法转换'System.Linq.IQueryable< AnonymousType＃1> ;'to'System.Linq.ParallelQuery< AnonymousType＃2>'
  

对于那个大块但是我已经试图解释我在做什么之前所做的一切。
感谢你将来的答案。

解决方案

问题是你的匿名类型是不一样的。 p>

一个是 {？ NumLot，？ EtatLot，string NomEmploye} ，另一个是 {？ NumLot，？ EtatLot，string test} 。最后一位成员名称不同，因此是不同的类型。

请尝试这样做：

  var listeLotControle = 
（
 from x in entBoum.LOT 
 join aff in entBoum.AFFECTATION_LOT on x.NumLot equals aff.NumLot 
 join emp in entBoum.EMPLOYE on aff.IdEmploye等于emp.IdEmploye 
其中x.EtatLot.Contains（Libéré）|| x.EtatLot.Contains（Suspendu）|| x.EtatLot.Contains（Démarré） 
选择新的{x.NumLot，x.EtatLot，emp.NomEmploye} 
）.Union 
（
 from x in entBoum.LOT 
其中x.EtatLot。包含（Démarré）
选择新的{x.NumLot，x.EtatLot，NomEmploye = test} 
）; 
  

I'm kind of stuck with that problem. Hope i'll get some help. Here's the point. I have to fill my DataGridView with that SQL request :

SELECT LOT.NumLot, EtatLot, NomEmploye FROM LOT
JOIN AFFECTATION_LOT on LOT.NumLot=AFFECTATION_LOT.NumLot
JOIN EMPLOYE on AFFECTATION_LOT.IdEmploye=EMPLOYE.IdEmploye
WHERE EtatLot='Libéré' or EtatLot='Suspendu' or EtatLot='Démarré'
UNION
SELECT NumLot, EtatLot, null FROM LOT
WHERE EtatLot='Démarré'

First i've used "null" value in my second "SELECT" because "UNION" need to have 3 arguments like the first "SELECT" and there is no "NomEmploye" data in my table LOT. Anyway that request is working well in SQL. But when i try to use it in LINQ

string test = "null";
var listeLotControle = (from x in entBoum.LOT
                        join aff in entBoum.AFFECTATION_LOT on x.NumLot equals aff.NumLot
                        join emp in entBoum.EMPLOYE on aff.IdEmploye equals emp.IdEmploye
                        where x.EtatLot.Contains("Libéré") || x.EtatLot.Contains("Suspendu") || x.EtatLot.Contains("Démarré")
                        select new { x.NumLot, x.EtatLot, emp.NomEmploye }).Union
                        (from x in entBoum.LOT
                        where x.EtatLot.Contains("Démarré")
                        select new { x.NumLot, x.EtatLot, test });
dataGridViewAffectationLotControleur.DataSource = listeLotControle.ToList();

I have that 3 errors in Visual Studio and i don't really understand it.

Error 1 Argument instance: can not convert 'System.Linq.IQueryable AnonymousType # 1>' to 'System.Linq.ParallelQuery <AnonymousType # 2>'
Error 2 'System.Linq.IQueryable <AnonymousType # 1>' does not contain a definition for 'Union' and the best overload the extension method 'System.Linq.ParallelEnumerable.Union <TSource> (System.Linq.ParallelQuery <TSource>, System.Collections.Generic.IEnumerable <TSource>) '
Error 3 type arguments for method 'System.Linq.Enumerable.ToList <TSource> (System.Collections.Generic.IEnumerable <TSource>)' can not be inferred from the use. Try specifying the type arguments explicitly.

As i can see, the problem is due to the <AnonymousType>.... But that don't help me so much right now. I've also tried that way to make it work

IQueryable listeLotControle;
string test = "null";
listeLotControle = (from x in entBoum.LOT
                        join aff in entBoum.AFFECTATION_LOT on x.NumLot equals aff.NumLot
                        join emp in entBoum.EMPLOYE on aff.IdEmploye equals emp.IdEmploye
                        where x.EtatLot.Contains("Libéré") || x.EtatLot.Contains("Suspendu") || x.EtatLot.Contains("Démarré")
                        select new { x.NumLot, x.EtatLot, emp.NomEmploye }).Union
                        (from x in entBoum.LOT
                        where x.EtatLot.Contains("Démarré")
                        select new { x.NumLot, x.EtatLot, test });
dataGridViewAffectationLotControleur.DataSource = listeLotControle.ToList();

But i've got same errors plus that one

Error 4 'System.Linq.IQueryable' does not contain a definition for 'ToList' and no extension method 'ToList' accepting a first argument of type 'System.Linq.IQueryable' was found (a using directive or an assembly reference is it missing?)

I maybe need a Using, but which one? (I precise that i already use using System.Linq;)

Finally i've tried that last method.

string test = "null";
var listeLotControle = from x in entBoum.LOT
                         join aff in entBoum.AFFECTATION_LOT on x.NumLot equals aff.NumLot
                         join emp in entBoum.EMPLOYE on aff.IdEmploye equals emp.IdEmploye
                         where x.EtatLot.Contains("Libéré") || x.EtatLot.Contains("Suspendu") || x.EtatLot.Contains("Démarré")
                         select new { x.NumLot, x.EtatLot, emp.NomEmploye };
var listeLotControle2 = from x in entBoum.LOT
                         where x.EtatLot.Contains("Démarré")
                         select new { x.NumLot, x.EtatLot, test };
var union = listeLotControle.Union(listeLotControle2);
dataGridViewAffectationLotControleur.DataSource = listeLotControle2.ToList();

But i still have these errors

Error 1 'System.Linq.IQueryable <AnonymousType # 1>' does not contain a definition for 'Union' and the best overload the extension method 'System.Linq.ParallelEnumerable.Union <TSource> (System.Linq.ParallelQuery <TSource>, System.Collections.Generic.IEnumerable <TSource>) 'contains invalid arguments
Error 2 Argument instance: can not convert 'System.Linq.IQueryable <AnonymousType # 1>' to 'System.Linq.ParallelQuery <AnonymousType # 2>'

Sorry for that big block but i've tried to explain all what i did before asking you. Thanks for your future answers.

解决方案

The problem is that your anonymous types are not the same type.

One is { ? NumLot, ? EtatLot, string NomEmploye } and the other is { ? NumLot, ? EtatLot, string test }. The last member has a different name hence it is a different type.

Try this instead:

var listeLotControle =
(
    from x in entBoum.LOT
    join aff in entBoum.AFFECTATION_LOT on x.NumLot equals aff.NumLot
    join emp in entBoum.EMPLOYE on aff.IdEmploye equals emp.IdEmploye
    where x.EtatLot.Contains("Libéré") || x.EtatLot.Contains("Suspendu") || x.EtatLot.Contains("Démarré")
    select new { x.NumLot, x.EtatLot, emp.NomEmploye }
).Union
(
    from x in entBoum.LOT
    where x.EtatLot.Contains("Démarré")
    select new { x.NumLot, x.EtatLot, NomEmploye = test }
);

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