如何在Visual Basic中使用LINQ to Entities？ [英] How do I use LINQ to Entities in Visual Basic?

问题描述

1. ToyData（Visual Basic Class Library）

   >



2. ToyOne（Visual Basic WPF应用程序）

ToyData项目包含一个由玩具数据库生成的ADO.NET实体数据模型Toy.edmx 。

ToyOne项目包含这个 Window1.xaml.vb文件：

 
 1导入ToyData 
 2 
 3类Window1 
 4 
 5 Private Sub Window1_Loaded（_ 
 6 ByVal sender As System.Object，_ 
 7 ByVal e As System.Windows.RoutedEventArgs）_ 
 8处理MyBase。加载
 9 
 10 Dim dc作为新的ToyEntities 
 11 Label1.Content =（从c作为客户端在dc.ClientSet _ 
 12选择c）.First 
 13 
 14 End Sub 
 15 
 16结束类
 

它将抛出此运行时异常自动生成

 
配置中找不到指定的命名连接，
不适用于EntityClient提供者，或无效。 
 

我做错了什么？

解决方案

我在服务项目和测试项目（使用服务中定义的数据对象）之前看过这个问题。

---

如果您右键点击新玩具实用程序，然后进行定义，并继续钻取...您将获得一些自动生成的代码，从中获取连接字符串一个配置文件。

检查ToyData项目中的配置文件。将值复制到另一个项目的App.Config文件（可能还不存在）。

I've created a .NET solution with two projects:

1. ToyData (Visual Basic Class Library)

2. ToyOne (Visual Basic WPF Application)

The ToyData project contains Toy.edmx, an ADO.NET Entity Data Model generated from a database called Toy.

The ToyOne project contains this Window1.xaml.vb file:

1   Imports ToyData
2   
3   Class Window1
4   
5       Private Sub Window1_Loaded( _
6       ByVal sender As System.Object, _
7       ByVal e As System.Windows.RoutedEventArgs) _
8       Handles MyBase.Loaded
9   
10          Dim dc As New ToyEntities
11          Label1.Content = (From c As Client In dc.ClientSet _
12                            Select c).First
13  
14      End Sub
15  
16  End Class

It throws this run-time exception in the auto-generated Toy.Designer.vb file:

The specified named connection is either not found in the configuration,  
not intended to be used with the EntityClient provider, or not valid.

What am I doing wrong?

解决方案

I've seen this issue before between a service project and a test project (that uses the data objects defined in the service).

---

If you right click on "new ToyEntities" and go to definition, and keep drilling in... you'll get to some auto-generated code that fetches a connection string from a config file.

Check the ToyData project for a config file. Copy the values into an App.Config file (it may not exist yet) for the other project.

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