How to configure Mutlilayer C# .Net Core Project for use of Entity Framework Core?

Question

The situation

I'm working on a school project and I use Blazor (Server-Side) for the Frontend. I do have a business layer and a DataAcces Layer (both .Net Core Class Libraries). I'm using Code First to create an SQLite database.

The problem/error

I somehow get following messages when trying to execute Add-Migration InitialCreate:

The warning

An error occurred while accessing the Microsoft.Extensions.Hosting services. Continuing without the application service provider. Error: 'AddDbContext' was called with configuration, but the context type 'TemperBapesContext' only declares a parameterless constructor. This means that the configuration passed to 'AddDbContext' will never be used. If configuration is passed to 'AddDbContext', then 'TemperBapesContext' should declare a constructor that accepts a DbContextOptions and must pass it to the base constructor for DbContext.

The error

No database provider has been configured for this DbContext. A provider can be configured by overriding the 'DbContext.OnConfiguring' method or by using 'AddDbContext' on the application service provider. If 'AddDbContext' is used, then also ensure that your DbContext type accepts a DbContextOptions object in its constructor and passes it to the base constructor for DbContext.

Project Architecture and Description

The Startup project is my Blazor application.

My appsettings.json contains the ConnectionString to the database:

  "ConnectionStrings": {
    "SQLite": "Data Source=L:\\M183\\m183\\project\\SQLite\\TemperBapesDB.db;"
  }

My Startup.cs ConfigureServices() looks like this:

public void ConfigureServices(IServiceCollection services)
{
    services.AddRazorPages();
    services.AddServerSideBlazor();
    services.AddBussinesLayer(Configuration);
}

The SetupExtensions.cs on Business Level looks like this:

public static void AddBussinesLayer(this IServiceCollection services, IConfiguration configuration)
{
    services.AddDataAccess(configuration);
}

The SetupExtensions.cs on DataAccess Level looks like this:

public static void AddDataAccess(this IServiceCollection services, IConfiguration configuration)
{
    services.AddDbContext<TemperBapesContext>(options => options.UseSqlite(configuration.GetConnectionString("SQLite")));
}

NuGet-Packages Installed

Blazor project:

Microsoft.EntityFrameworkCore.Design

Business Layer:

Microsoft.Extensions.Configuration.Abstractions
Microsoft.Extensions.DependencyInjection.Abstractions

DataAccess Layer:

Microsoft.EntityFrameworkCore
Microsoft.EntityFrameworkCore.Sqlite
Microsoft.EntityFrameworkCore.Tools

@devNull Not exactly but Cem.S has answered my question below. — Eldar Omerovic, Nov 27 '20 at 17:04
not sure how that doesn't answer it, since it's the same error and same answer — devNull, Nov 27 '20 at 17:07
Oh I actually looked at the post because your link points to the question and not the answer. You're able to get the link of answers directly. But thank you as well! — Eldar Omerovic, Nov 27 '20 at 17:10

score 1 · Accepted Answer · answered Nov 27 '20 at 16:56

1

public class TemperBapesContext : DbContext
{
    // Your DbSets 

    // This constructor is needed
    public TemperBapesContext(DbContextOptions<TemperBapesContext> options)
        : base(options)
    {
    }
}

You need to add a constructor where DbContextOptions can be injected

answered Nov 27 '20 at 16:56

Cem.S

1,001
10
15

Omg I feel so embarrassed right now. I've searched for a solution everywhere but there. Thanks a lot! Already worked with this kind of projects I just forgot a lot of things again. – Eldar Omerovic Nov 27 '20 at 17:01

How to configure Mutlilayer C# .Net Core Project for use of Entity Framework Core?

1 Answers1