How to seed data in .NET Core 6 with Entity Framework?

Question

I know how to seed data to a database with old .NET 5.0 in startup.cs file using my Seeder class with a Seed() method creating some initial data.

public void Configure(IApplicationBuilder app, IHostingEnvironment env, Seeder seeder)
{
   seeder.Seed();

   ..............
   // other configurations
}

How do I do this in .NET 6.0? There is no place to add my Seeder class as an argument.

Answer 1

I have never use your solution before. This is what I'm doing,

public class DataContext: DbContext
{
    public DataContext(DbContextOptions options) : base(options)
    {
        
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        new DbInitializer(modelBuilder).Seed();
    }
    
    // Db sets
}

And

public class DbInitializer
{
    private readonly ModelBuilder modelBuilder;

    public DbInitializer(ModelBuilder modelBuilder)
    {
        this.modelBuilder = modelBuilder;
    }

    public void Seed()
    {
        modelBuilder.Entity<User>().HasData(
               new User(){ Id = 1.... },
               new User(){ Id = 2.... },

        );
    }
}

Then run the command

dotnet ef migrations add .......

To create migration file

And

dotnet ef database update

To update db

Answer 2

I solved a similar problem as follows:

Program.cs (.NET 6)

...
builder.Services.AddScoped<IDbInitializer, DbInitializer>(); //can be placed among other "AddScoped" - above: var app = builder.Build();   

...    
SeedDatabase(); //can be placed above app.UseStaticFiles();
...    
    void SeedDatabase() //can be placed at the very bottom under app.Run()
    {
        using (var scope = app.Services.CreateScope())
        {
            var dbInitializer = scope.ServiceProvider.GetRequiredService<IDbInitializer>();
            dbInitializer.Initialize();
        }
    }