How to add base.OnModelCreating() from the Identity context to the model context?

Question

I watched this YouTube video at timeframe 24:30 minutes, adding the base.OnModelCreating(builder) to the model context and received this error, "Cannot use local variable or local function 'builder' declared in a top-level statement in this context"

https://www.youtube.com/watch?v=5X9ogJVWAjE&t=110s

Any pointers much appreciated as it's driving me mad!

Answer 1

Hi @Joe

I followed the tutorial and created a sample, everything works well.

In my sample, the Identity's DbContext like this:

public class TestIdentityContext : IdentityDbContext<IdentityUser>
{
    public TestIdentityContext(DbContextOptions<TestIdentityContext> options)
        : base(options)
    {
    }
    protected TestIdentityContext(DbContextOptions options)
    : base(options)
    {
    }
    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);
        // Customize the ASP.NET Identity model and override the defaults if needed.
        // For example, you can rename the ASP.NET Identity table names and more.
        // Add your customizations after calling base.OnModelCreating(builder);
    }
}

The DB first generated DBContext (SecondDbContext) as below: Note: it inherits the Identity's DbContext: TestIdentityContext

public partial class SecondDbContext : TestIdentityContext
{ 
    public SecondDbContext(DbContextOptions<SecondDbContext> options)
        : base(options)
    {
    }
     
    public virtual DbSet<Customer> Customers { get; set; }

    public virtual DbSet<Employee> Employees { get; set; }
 
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    { 
        base.OnModelCreating(modelBuilder);
        modelBuilder.Entity<Customer>(entity =>
        {
            entity.ToTable("Customer");
        });

        modelBuilder.Entity<Employee>(entity =>
        {
            entity.HasKey(e => e.EmpId);
        });

        OnModelCreatingPartial(modelBuilder);
    }

    partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
}

In the SecondDbContext's OnModelCreating method, if we use the following code, it will throw the "Cannot use local variable or local function 'builder' declared in a top-level statement in this context" error. So, for this error, please check your code and make sure you are using the same variable name.

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    { 
        base.OnModelCreating(builder);

Then in the Program.cs file, use the following code to register the DbContext and Service:

builder.Services.AddDbContext<SecondDbContext>(options =>
    options.UseSqlServer(connectionString));

builder.Services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
    .AddEntityFrameworkStores<SecondDbContext>();
//register the service
builder.Services.AddTransient<IDataService, DataService>();

The service as below:

    public interface IDataService
    {
        List<Employee> GetEmployees(string gender);
    }
    public class DataService : IDataService
    {
        private readonly SecondDbContext _context;
        public DataService(SecondDbContext secondDbContext)
        {
            _context = secondDbContext;
        }
        public List<Employee> GetEmployees(string gender)
        {
            var result  = new List<Employee>();
            if(string.IsNullOrEmpty(gender))
            {
                result= _context.Employees.ToList();
            }
            else
            {
              result  = _context.Employees.Where(c => c.Gender == gender).ToList();
            }

            return result;

        }
    }

Then in the Privacy.cshtml page:

    [Authorize]
    public class PrivacyModel : PageModel
    {
        private readonly ILogger<PrivacyModel> _logger;
        private readonly IDataService _dataService;

        public PrivacyModel(ILogger<PrivacyModel> logger, IDataService dataService)
        {
            _logger = logger;
            _dataService=dataService;
        }
        public List<Employee> MyEmployees { get; set; }
        public void OnGet()
        {
            MyEmployees = _dataService.GetEmployees("Male");
        }
    }

After running the application, the code works well:

Besides, from your code, it seems that there have three DbContexts in your project: AppDbContext, ApplicationDbContext and Data_IdentityContext, please check them carefully. Or you can followed the tutorial and create a sample again. If still not working, please share your project.

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Best regards,

Dillion

Answer 2

Probably you must write this:

protected override void OnModelCreating( ModelBuilder builder )
{
   base.OnModelCreating(builder);

}

Show some details about your code and builder variable.