Digging Into Blazor - Integrating with Entity Framework

April 4, 2023
4 Minute Read

Now that I was getting my feet wet, it was time for me to start laying out the framework for my first real Blazor project. Step one was to get the database setup.

This is the second post in a multi-part series. If you haven't read part one, you can read about my first impressions.

Series: Digging into Blazor

I had already decided to use Entity Framework to interact with my SQL server. I have used Entity Framework plenty in the past so I was familiar with the basics. If you haven't used Entity Framework, I would highly recommend reading about it and going through some tutorials. Microsoft provides some great documentation.

The first thing I did was look into how to use Entity Framework with Blazor.

In Blazor Server apps, scoped service registrations can be problematic because the instance is shared across components within the user's circuit.

Well that's different.

I quickly realized that things were a little different, but following their setup, I worked to make sure that each interaction would operate in its own context. Reading more I found out that Microsoft recommended I use a factory to help. I added the DB Factory to my Program.cs file. The nice part is that it's very similar to how I configure it in my other projects.

// Program.cs

builder.Services.AddDbContextFactory<ApplicationDbContext>(opt =>

Setting up my models worked the same way as Digital Family Cookbook.

Let's create my first database table and model. Each of my baseball cards are going to need a brand (think Topps, Donruss, or Upper Deck).

// BrandDto.cs

namespace CardOrganizer.Domain.Dtos;

public class BrandDto
    public int BrandId { get; set; }

    public string Name { get; set; } = string.Empty;

    public int CardTypeId { get; set; }

    public bool IsActive { get; set; } = true;

    public List<BaseballCardDto> BaseballCards { get; set; } = new List<BaseballCardDto>();

Now let's actually create the app's database context.

// ApplicationDbContext.cs

namespace CardOrganizer.Infrastructure.Database;

public class Role : IdentityRole<int> {}

public class ApplicationDbContext : IdentityDbContext<UserAccountDto, IdentityRole<int>, int>
    public DbSet<BrandDto> Brands { get; set; }

    public DbSet<BaseballCardDto> BaseballCards { get; set; }

    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) : base(options)


	protected override void OnModelCreating(ModelBuilder builder)


		#region "Brand"
            .ToTable("Brand", schema: "card");

            .HasKey(b => b.BrandId)

            .Property(b => b.CardTypeId)

            .Property(b => b.Name)
        #endregion "Brand"

You can ignore the Role and Identity declarations as I'll get into those in the next post, but it was familiar to me to use the Fluent API to build the model that Entity Framework will use to build the tables in the database.

To build the database, I used the standard EF terminal commands

$ dotnet ef migrations add AddBrandModels

And then once that succeeded:

$ dotnet ef database update

Now that the database was built, I can interact with the database using the IDbContextFactory I added to my Program.cs file above.

// BrandRepository.cs

namespace CardOrganizer.Infrastructure.Repositories;

public class BrandRepository : IBrandRespository
    private readonly IDbContextFactory<ApplicationDbContext> _contextFactory;

    public BrandRepository(IDbContextFactory<ApplicationDbContext> contextFactory)
        _contextFactory = contextFactory;

    public Brand GetById(int brandId)
        var dbContext = _contextFactory.CreateDbContext();

        var brand = dbContext.Brands.FirstOrDefault(b => b.BrandId == brandId);

        if (brand is null)
            throw new ObjectNotFoundException("Unable to find the specified brand");

        return Brand.FromDto(brand);

You can see in the constructor, I use dependency injection to inject the DbContextFactory to use in the repo, so that in any method I need access to the DB, I can easily create a new DB context by:

var dbContext = await _contextFactory.CreateDbContextAsync();

From there on, there's no real difference between using Entity Framework in a Blazor app or a .NET Web API.

The one thing you might also notice is that I don't have the repository return the DTO (Data Transfer Object) from the repository. Instead I have it return the domain model. My reasoning for that is that I want any extra logic I might need in the model separate from the model that gets saved and retrieved from the database. For the Brand domain model, the FromDto function is pretty simple.

public static Brand FromDto(BrandDto dto) => new Brand
    BrandId = dto.BrandId,
    Name = dto.Name,
    CardType = (Constants.CardType)dto.CardTypeId,
    IsActive = dto.IsActive,

In the next post, my plan is to dig into dealing with authentication in Blazor. It was probably the biggest stumbling block I faced so far.