Htykuut

I have a .NET Core class library that is the data access layer for multiple web applications. I am using Entity Framework Core 1.1, but I'm having trouble with migrations through PMC. My initial migration worked successfully, but after updating the database and re-launching VS 2017 I get a null exception on the contentRootPath argument when attempting to migrate. I may have made some changes to the project after my successful migration, but I don't remember what they were. This is the error and stack trace:

Both Entity Framework Core and Entity Framework 6 are installed. The Entity Framework Core tools are running. Use 'EntityFrameworkAdd-Migration' for Entity Framework 6.

System.ArgumentNullException: Value cannot be null.

Parameter name: contentRootPath

   at Microsoft.EntityFrameworkCore.Utilities.Check.NotEmpty(String value, String parameterName)

   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations..ctor(IOperationReporter reporter, Assembly assembly, Assembly startupAssembly, String environment, String projectDir, String contentRootPath, String rootNamespace)

   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.<>c__DisplayClass4_0.<.ctor>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)

There is no config file in my migrations directory, and I can't find anything related in the DbContext class. Has anyone else ran into this issue, or know what is causing it?

SqlDbContext class:

using Microsoft.EntityFrameworkCore;

using DataLayer.Models.User;



namespace DataLayer.Context 

{

  public class SqlDbContext : DbContext

  {

      public DbSet<User> Users { get; set; }



      protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

      {

          optionsBuilder.UseSqlServer(MyDbConfig.SqlConnectionString);   

      }



      protected override void OnModelCreating(ModelBuilder modelBuilder)

      {

          modelBuilder.Entity<User>()

              .Ignore(m => m.FullName);



          base.OnModelCreating(modelBuilder);

      }

   }

}

It turns out that this was due to the Microsoft.EntityFrameworkCore.Tools package being pre-release version 2.0.0, which is not currently a stable version. Downgrading to 1.1.1 fixed the issue.

I had this issue in the past and here is the fix:

First, make sure that the version of the SDK you are using is 2.1.200 as you are under Core 1.1 and put this on your global.json:

{

  "sdk": {

    "version": "2.1.200"

  }

}

Add reference on your .csproj to Microsoft.EntityFrameworkCore.Design and Microsoft.EntityFrameworkCore.Tools.DotNet so you will have:

 <ItemGroup>

    <PackageReference Include="Microsoft.EntityFrameworkCore.Design"

                      Version="1.1.6"

                       PrivateAssets="All" />

  </ItemGroup>

  <ItemGroup>

     <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet"

                            Version="1.1.6" />

  </ItemGroup>