为什么VS 2015需要引用System.Data.Entity但VS 2013不需要？ [英] Why does VS 2015 need a reference to System.Data.Entity but VS 2013 does not?

问题描述

我已经安装了VS 2015（虽然我之前安装了RC，但不是RC）。我打开了一个现有的解决方案，该解决方案在VS 2013中运行良好，并出现以下错误。

I've installed VS 2015 (not the RC though I had that installed prior). I opened an existing solution that was working fine in VS 2013 and got the following error.

BC30652组装'System.Data所需的引用。实体，
版本= 4.0.0.0，区域性=中性，PublicKeyToken = b77a5c561934e089'
，其中包含类型'EntityObject'。将一个添加到您的项目中。

BC30652 Reference required to assembly 'System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' containing the type 'EntityObject'. Add one to your project.

我按照VS的建议在项目中添加了对System.Data.Entity的引用，它可以正常工作。但是，我想知道为什么会这样。

I added a reference to System.Data.Entity in the project as VS suggested and it worked. However, I'm wondering why this happened.

如果删除System.Data.Entity引用，则VS 2013仍然有效，但VS 2015会引发错误。该项目确实有对System.Data的引用。

If I remove System.Data.Entity reference, VS 2013 still works but VS 2015 throws errors. The project does have a reference to System.Data.

有关解决方案的说明：

• 最初在VS 2013中开发


• .NET 4.0


• 还引用了System.Data


• 有2个项目，一个主要项目（导致错误）和DAL


• DAL具有实体数据模型（.edmx）

• Originally developed in VS 2013
• .NET 4.0
• Also has reference to System.Data
• Has 2 projects, a main (which causes the error) and a DAL
• The DAL has an Entity Data Model (.edmx)

推荐答案

我得到了Visual Basic语言团队的确认，这很可能是由于Visual Studio 2015中的编译器发生了更改：

I got confirmation from the Visual Basic language team that this is very likely due to a change in their compiler in Visual Studio 2015:

...实际上，我们确实在努力使事情变得宽松。但总结是，编译器可能需要更多引用才能确保正确性。如果可以，请添加它们。我相信如果您调用灯泡，可以快速解决此问题。

... we actually did work to try to make things more permissive. But the summary is that the compiler may require more references for correctness. Add them if you can. I believe there is a quick fix for it if you invoke the light bulb.

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