Add-Migration Value cannot be null. Parameter name: language

Question

I am trying to create a new migration but I get an System.ArgumentNullException saying:

System.ArgumentNullException: Value cannot be null.
Parameter name: language
    at Microsoft.EntityFrameworkCore.Utilities.Check.NotNull[T](T value, 
    String parameterName)
    at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations..ctor
    (IOperationReporter reporter, Assembly assembly, Assembly 
    startupAssembly, String projectDir, String rootNamespace, String 
    language)
    at Microsoft.EntityFrameworkCore.Design.OperationExecutor.<>c__DisplayClass4_0.<.ct
    or>b__4()
    at Microsoft.EntityFrameworkCore.Internal.LazyRef`1.get_Value()
    at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType)
    at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
    at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Value cannot be null.
Parameter name: language

Possible duplicate of Error with Entity Framework add-migration: "value cannot be null" — Oleksii Klipilin
– Oleksii Klipilin, Commented Mar 7, 2018 at 11:52

bricelam · Accepted Answer · 2018-03-09 17:59:00Z

11

This is issue #11075. The version of your tool doesn't match the version of your runtime. Ensure you've updated every Microsoft.EntityFrameworkCore package to 2.1.0-preview1-final.

answered Mar 9, 2018 at 17:59

bricelam

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4 Comments

Dano Over a year ago

Possibly a different code path for scaffolding vs. migrations? I was hitting the error while doing a db migration. Just saying for me the problem appears to be from a bug introduced in the 2.1.0 Final. Downgrading to 2.0.1 will fixed my issue with migration. Added a detailed note with repro steps in the 11075 issue.

animalito maquina Over a year ago

For me the not updated package was the <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="2.1.0-preview1-final" /> inside csproj

code5 Over a year ago

@animalitomaquina - yup this was it for me as well. Thanks! I need this version for now, because v2.0.2 doesn't support Ambient Transactions.

curiousBoy Over a year ago

Thanks, this even was the case for EF6 but helped me as soon as I updated all the projects references to EF to latest version (as of now it is 6.4.4)

Peter Húbek · Accepted Answer · 2018-03-07 15:54:38Z

6

It's related to the EF Core not EF6, it looks like there is a bug in the 2.1.0.preview1-final version.

Check the version you are running with dotnet ef --version

Downgrade to the Microsoft.EntityFrameworkCore.Design 2.0.1 version.

answered Mar 7, 2018 at 15:54

Peter Húbek

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1 Comment

Scott Alexander Over a year ago

Cheers, been scratching my head for a while on this one.

4b0 · Accepted Answer · 2023-08-18 08:03:28Z

4

If it is EF 6.x.x, then use VS2019.

Ref: https://github.com/dotnet/ef6/issues/1870

edited Aug 18, 2023 at 8:03

4b0

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answered Aug 18, 2023 at 7:58

Sasika Miyuran

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1 Comment

Mohamed Badr Apr 25 at 12:36

No need, just update EF to 6.5.1

Zin Min · Accepted Answer · 2018-05-21 08:57:03Z

0

For EF Core for .NET Core 2.0.1 in VS 2017 Version 15.7.1, I removed DotNetCliToolReference element from my project file.

answered May 21, 2018 at 8:57

Zin Min

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Comments

zappa · Accepted Answer · 2019-09-25 10:51:15Z

0

I think this is a bug.
I'm using EF Core 2.2.4, i'm trying to rollback a migration with:

migrationBuilder.DropIndex(name: "myIndexName");

This was auto-generated for me by EF.
The method signature says name is the only required parameter (there's 2 optional ones after). When i run this i get this:

System.ArgumentNullException: Value cannot be null.
Parameter name: name

but if i add a second parameter for the table name it works:

migrationBuilder.DropIndex(
                name: "myIndexName",
                table: "myTableName");

answered Sep 25, 2019 at 10:51

zappa

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Comments

Mohamed Badr · Accepted Answer · 2025-04-25 14:12:09Z

0

I encountered the same error in Visual Studio 2022, and updating Entity Framework to version 6.5.1 resolved the issue.

answered Apr 25 at 14:12

Mohamed Badr

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