CODEWITHSUNDEEP
c#dependency-injectionentity-framework-core.net-5
Gabriel Anton
Gabriel Anton

Reputation: 624

Add Migration: Unable to create an object of type AppContext

I have a .NET 5 solution that contains two projects (DataLayer and ServiceLayer). In DataLayer i have the following DbContext:

internal class ApplicationContext
    : DbContext
{
    public ApplicationContext(DbContextOptions<ApplicationContext> options)
        : base(options)
    {
    }
    public virtual DbSet<User> Users { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.ApplyConfigurationsFromAssembly(GetType().Assembly);
    }
}

and the following DbContextFactory:

internal sealed class ContextFactory
    : IDbContextFactory<ApplicationContext>
{
    public ContextFactory(DbContextOptions<ApplicationContext> options)
    {
        Options = options ?? throw new ArgumentNullException(nameof(options));
    }

    private DbContextOptions<ApplicationContext> Options { get; }

    public ApplicationContext CreateDbContext()
    {
        return new ApplicationContext(Options);
    }
}

which i use in each repository ctor:

 public UserRepository(IDbContextFactory<ApplicationContext> contextFactory) { ... }

And the services initialization for DbContextFactory:

services.AddDbContextFactory<ApplicationContext>(options =>
{
    options
    .UseLazyLoadingProxies()
    .UseSqlServer(connectionString);
});

The problem is when i try to create a migration i get the following message:

Unable to create an object of type 'ApplicationContext'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728 for both of commands:

Add-Migration Initial

dotnet ef migrations add Initial --project DataLayer

I also have to mention that both projects are plain .NET 5 library projects and, in the service layer project, i build the ServiceCollection manually: var services = new ServiceCollection();

I searched for solutions but i didn't find any.

Thanks

Upvotes: 1

Views: 4297

Answers (1)

Maxim Tkachenko
Maxim Tkachenko

Reputation: 5808

I think you can't inject anything into constructor. You should use the way described in documentation:

public class BloggingContextFactory : IDesignTimeDbContextFactory<BloggingContext>
{
    public BloggingContext CreateDbContext(string[] args)
    {
        var optionsBuilder = new DbContextOptionsBuilder<BloggingContext>();
        optionsBuilder.UseSqlite("Data Source=blog.db");

        return new BloggingContext(optionsBuilder.Options);
    }
}

Then you can pass any parameters through args:

dotnet ef database update -- --environment Production --connectionstring "some_connection_string"

Upvotes: 3

Related Questions