问题
I have a netstandard20 project that references a .Net 4.6 Project, all compiles and runs except where I call any functionality in the .Net 4.6 project, I get the following error.
FileNotFoundException: Could not load file or assembly 'System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
In VS 2017, in the project explorer under Dependancies / SDK / Microsoft.NETCore.App I can see System.Data.dll and System.Data.Common.dll but no reference to System.Data.Linq.dll, I am assuming this is my problem and it has not been pulled in.
How do I get my project to include System.Data.Linq.dll?
If I include C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6\System.Data.Linq.dll I get the following error
BadImageFormatException: Could not load file or assembly 'System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. Reference assemblies should not be loaded for execution. They can only be loaded in the Reflection-only loader context. (Exception from HRESULT: 0x80131058)
回答1:
System.Data.Linq is not part of .NET Standard 2.0 and .NET Core 2.0 and therefore cannot be used on that platform.
Even tough you have been able add a reference to a .NET 4.6 project via the compatibility shims, it fails at runtime because of a feature that is not available on the target runtime
回答2:
I was able to solve my need to use System.Data.Linq in a .NET Standard 2.0 library by using the Mindbox.Data.Linq NuGet package.
After installing it you should be able to use the System.Data.Linq namespace just like you could when writing for .NET Framework!
来源：https://stackoverflow.com/questions/45935148/system-data-linq-in-netstandard20