Value cannot be null - In-Memory Database .Net - sql

Question

I am trying to use a In-Memory Database, but I get this message:
System.ArgumentNullException: 'Value cannot be null. (Parameter
'source')'
I read a lot some similar question related with this issue, but every article is related with the connection String, and I think I must not use a ConnectionString because is a In-Memory Database. What Do I do wrong? I leave my code:
DbInitializer.cs - In this class appears the error
public static class DbInitializer
{
public static void Initialize(IServiceProvider serviceProvider)
{
using (var _context = new AppDBContext(serviceProvider.GetRequiredService<DbContextOptions<AppDBContext>>()))
{
if (_context.AgentsRole.Any()) //In this line appears the error
return;
_context.AgentsRole.AddRange(
new Agent { Id = 1, Role_Name = "David Lopez", Is_Active = true, Role_Description = "This is a test for David Lopez" },
new Agent { Id = 2, Role_Name = "James Norris", Is_Active = false, Role_Description = "This is a test for James Norris" },
new Agent { Id = 3, Role_Name = "Jhon Norris", Is_Active = true, Role_Description = "This is a test for Jhon Norris" },
new Agent { Id = 4, Role_Name = "James Norr", Is_Active = true, Role_Description = "This is a test for James Norr" }
);
_context.SaveChanges();
}
}
}
Startup.cs:
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<AppDBContext>(options=> options.UseInMemoryDatabase(databaseName: "InMemory_DB"));
services.AddControllers();
services.AddSwaggerGen();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseHttpsRedirection();
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
app.UseSwagger();
app.UseSwaggerUI(c =>
{
c.SwaggerEndpoint("/swagger/v1/swagger.json", "My Test1 Api v1");
});
}
}
Program.cs:
public class Program
{
public static void Main(string[] args)
{
var host = CreateHostBuilder(args).Build();
using (var scope = host.Services.CreateScope())
{
var services = scope.ServiceProvider;
var context = services.GetRequiredService<AppDBContext>();
DbInitializer.Initialize(services);
}
host.Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseStartup<Startup>();
});
}
Controller.cs:
[ApiController]
[Route("api/[controller]")]
public class AgentRoleController : ControllerBase
{
private readonly ILogger<AgentRoleController> _logger;
private readonly AppDBContext _context;
public AgentRoleController(ILogger<AgentRoleController> logger, AppDBContext context)
{
_logger = logger;
_context = context;
}
[HttpGet]
[SwaggerOperation("GetAgentsRole")]
[SwaggerResponse((int)HttpStatusCode.OK)]
[SwaggerResponse((int)HttpStatusCode.NotFound)]
public IEnumerable<Agent> Get()
{
return _context.AgentsRole;
}
}
AppDBContext.cs:
public class AppDBContext : DbContext
{
public AppDBContext(DbContextOptions<AppDBContext> options)
:base(options)
{
}
public DbSet<Agent> AgentsRole;
}

Answer 1

The solution is in AppDBContext.cs, I missed the initialization of AgentsRole, the solution is:
public class AppDBContext : DbContext
{
public AppDBContext(DbContextOptions<AppDBContext> options)
:base(options)
{
}
public DbSet<Agent> AgentsRole { get; set; } // I added this Part!
}