I've verified that Entity Framework 6 Tools is installed as suggested in other answers on this site, but ADO.NET Entity Data Model never shows up in the New Items/Data list. I've also tried installing the .NET CORE 2.0 SDK as other answers have suggested to no avail.
To be clear, I'm not creating a .NET CORE application, I'm just trying to make a class library based on .NET framework 4.6. I created the project via .NET Standard and selected Class Library (.NET Standard).
I just need to install EF so I can do a code first generation from my existing SQL Server DB.
Don't use .NET Standard, select a .NET Framework project type.
.NET Standard is an abstract "Core or Framework" option, as if the naming wasn't confusing enough.
Related
I have a situation where an application uses various component libraries. The libraries were based on .NetStandard2.0/2.1 and internally used EF Core 3.1. For various deployment and development reasons, we now want to target EF Core 6.0, which raises the following issues.
Net Core 3.1 support runs out in December 2022 so we need to move away from it.
The application uses Net Framework functionality and cannot move to Net Core.
EF Core 6.0 does not support NetStandard, only Net 6.
Changing the library that uses EF Core to target NET 6 means that components referencing it also need to reference Net 6.
Dependencies trickle down to the application that targets Net Framework and, as a result, the application no longer builds because Net Framework is not compatible Net 6.
How can the Net Framework application use the Net 6 assembly? Or, more specifically, how can a Net Framework application use libraries that internally use EF Core 6.0?
The interface between the application (Net Framework) and the one single touch point library component (Netstandard) is very well defined. Maybe Pinvoke could solve the problem? Or something simpler that I have overlooked?
Somewhat related question: NU1202 Package Microsoft.EntityFrameworkCore 6.0.3 is not compatible with netstandard2.1
Other than process to process communication between .NET Framework and .NET 6, this is not supported (for example via a Web API or similar)
As a short term solution, you can change your .Net Standard 2.0 EF Core libraries to be multi targeted to both .Net Standard 2.0 (which will reference EF Core 3.1) and .Net 6 (which will reference EF Core 6). This will let your .Net Core apps use EF Core 6, while allowing your .Net Framework apps to use the same dlls, but to be using EF Core 3.1. I realize that EF Core 3.1 support ends December 2022, but it will keep things moving.
https://learn.microsoft.com/en-us/nuget/create-packages/multiple-target-frameworks-project-file
Btw, has Microsoft even attempted to address the fact that a .Net Framework application cannot reference .Net 6, therefore it cannot use EF Core 6? This is a major issue for us, as we were sold the idea that .Net Standard could be shared between .Net Framework and .Net Core, but this has ceased to be the case since .Net Standard 2.1 was introduced, and now MS has pushed all new features, like EF Core, to .Net 6.
And if not, will it be? If so, when?
I haven't been able to find any clear official information on this, and the limited information I was able to find on Stack Overflow is a year or two old.
I was able to find official information saying EF 6.3 will be able to be used in a .NET Core project, but I couldn't find a release date for it, nor am I sure what the implications for use in a .NET Standard project are.
EF 6 supports .NET Standard 2.1, which is currently supported by .NET Core 3.0 or later - no .NET Framework version. EF 6 also supports .NET 4.0 and 4.5 or later.
https://github.com/aspnet/EntityFramework6/blob/release/6.4/src/EntityFramework/EntityFramework.csproj#L6
Some clarification, since EntityFramework 6.3.0 .NET Standard 2.1 has been supported. However there is no .NET Framework version that supports .NET Standard 2.1. Comment from Microsoft:
NET Framework won't support .NET Standard 2.1 or later versions. For
more details, see the announcement of .NET Standard 2.1.
This means that a majority of all applications using EntityFramework 6.X won't be able to use the .NET Standard 2.1 project anyway.
https://learn.microsoft.com/en-us/dotnet/standard/net-standard
https://www.nuget.org/packages/EntityFramework/#
I am trying to use the ContainerConfiguration type from the Managed Extensibility Framework (MEF). According to here, it lives in "System.Composition.TypedParts.dll" which is part of .NET Framework 4.5. But I cannot find it in Add Reference for a .NET 4.5 application.
Where can I find this DLL?
It turned out to be part of MEF 2, which needs to be installed with NuGet. It's not distributed with .NET Framework.
I need to know if it is possible to start using the latest version of EF (4.3.1) with VS 2011 without having to install these CTP components as stated here.
I had these components installed but I removed them and since then I can't add a new edmx file to .net 4 targeted project; it complains about missing reference to System.Data.Entity.
Do I need to re install VS 2011?
After I removed and reinstalled Visual Studio, I still couldn't get red of the error, so I used process monitor to log what Visual Studio is doing with System.Data.Entity as a path filter, turned out that Visual Studio was reading from
C:\Windows\Microsoft.NET\assembly\GAC_MSIL\policy.4.0.system.data.entity v4.0_0.0.0.0__b77a5c561934e089\policy.4.0.system.data.entity.config
which had binding to the
System.Data.Entity.dll v 4.2.0.0
once I cleared the file VS was worked like charm.
The CTP uninstall left this out.
Yeah should work with no issues using .net 4, however theres a list of known issues when using .net 4.5. You dont need to re-install vs to get version 4.3.1 of entity framework, simply install it from the nuget package gallery and if you are using .net 4 it all seems to just work.
Issues listed when installing EF4.3.1 on .net 4.5 include those listed below.
Known Issues with Entity Framework 4.x and .NET Framework 4.5
Entity Framework 4.1 thru 4.3 included additional data annotations in the
System.ComponentModel.DataAnnotations namespace in the EntityFramework assembly.
In .NET 4.5 these annotations were moved to be part of the .NET Framework in the
System.ComponentModel.DataAnnotations.Schema namespace of the
System.ComponentModel.DataAnnotations.dll assembly. If you are using EF 4.x and targeting
.NET 4.5 this results in two data annotations with the same name in different assemblies.
Because the annotations in the .NET Framework are in a different namespace we were not
able to use type forwarding to avoid this conflict.
It is possible to use EF 4.x on .NET 4.5 but we recommend using the latest pre-release
version of EF 5. If you are not using the affected data annotations there is no impact
on your code. If you are using the data annotations in a C# project you can use the extern
modifier to ensure your code uses the annotations from EntityFramework.dll
(http://msdn.microsoft.com/en-us/library/e59b22c5(v=VS.80).aspx). If you use the new
annotations from the System.ComponentModel.DataAnnotations.dll assembly in .NET 4.5
they will not be processed by Code First.
The affected annotations are:
Column
ComplexType
DatabaseGenerated
DatabaseGeneratedOption
ForeignKey
InverseProperty
MaxLength
MinLength
NotMapped
Table
I have an MVC project that I would like to write in .NET 4.0
Is it possible to use Npgsql (which currently supports .net 3.5 ) if I will use it through Entity Framework, and I will limit myself to features of EF contained within 3.5?
Npgsql now supports .net 4.0 :D so question is no longer valid.