Unable to resolve service for type 'BusinessServices.CustomerBusinessService' while attempting to activate 'Repository.CustomerRepository' - asp.net-core

Question

Issue Message:
System.AggregateException: 'Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: Repository.ICustomerRepository Lifetime: Scoped ImplementationType: Repository.CustomerRepository': Unable to resolve service for type 'BusinessServices.CustomerBusinessService' while attempting to activate 'Repository.CustomerRepository'.)'
API Controller:
namespace WebAPIforAzureSQL.Controllers
{
[Route("api/[controller]")]
[ApiController]
[ApiVersion("1.0")]
[ApiVersion("2.0")]
public class AzureController : ControllerBase
{
private readonly ICustomerRepository customerRepository;
private readonly ICustomerBusinessService customerBusinessService;
public AzureController(ICustomerRepository _customerRepository, ICustomerBusinessService _customerBusinessService)
{
customerRepository = _customerRepository;
customerBusinessService = _customerBusinessService;
}
[MapToApiVersion("1.0")]
[HttpGet]
public IEnumerable<Customers> Customers()
{
return customerRepository.GetAllCustomers();
}
[MapToApiVersion("2.0")]
[HttpGet()]
public Customers OneCustomer([FromHeader] int customerID)
{
return customerRepository.GetCustomer(customerID);
}
[HttpGet()]
[ApiVersion("1.0")]
[ApiVersion("2.0")]
public bool NewCustomer([FromHeader] Customers c)
{
return customerRepository.AddCustomer(c);
}
}
}
Program.cs:
using Microsoft.AspNetCore.Mvc.Versioning;
using Microsoft.AspNetCore.Mvc;
using WebAPIforAzureSQL;
using Microsoft.EntityFrameworkCore;
using Repository;
using Microsoft.AspNetCore.Mvc.ApiExplorer;
using Contracts;
using BusinessServices;
var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddControllers().AddXmlSerializerFormatters();
builder.Services.AddSwaggerGen();
builder.Services.ConfigureOptions<ConfigureSwaggerOptions>();
builder.Services.AddApiVersioning(opt =>
{
opt.DefaultApiVersion = new ApiVersion(1, 0);
opt.AssumeDefaultVersionWhenUnspecified = true;
opt.ReportApiVersions = true;
opt.ApiVersionReader = ApiVersionReader.Combine(
new UrlSegmentApiVersionReader(),
new HeaderApiVersionReader("api-version")
);
});
// Add ApiExplorer to discover versions
builder.Services.AddVersionedApiExplorer(setup =>
{
setup.GroupNameFormat = "'v'VVV";
setup.SubstituteApiVersionInUrl = true;
});
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddDbContext<AmounDB001DbContext>(option =>
{
option.UseSqlServer(builder.Configuration.GetConnectionString("DB001"));
});
//adding Services
builder.Services.AddScoped<ICustomerRepository, CustomerRepository>();
builder.Services.AddScoped<ICustomerBusinessService, CustomerBusinessService>();
var app = builder.Build();
var apiVersionDescriptionProvider =
app.Services.GetRequiredService<IApiVersionDescriptionProvider>();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI(
options =>
{
foreach (var description in apiVersionDescriptionProvider.ApiVersionDescriptions)
{
options.SwaggerEndpoint($"/swagger/{description.GroupName}/swagger.json",
description.GroupName.ToUpperInvariant());
}
}
);
}
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run();
Repository Class
namespace Repository
{
public class CustomerRepository : ICustomerRepository
{
private readonly AmounDB001DbContext amounDB001DbContext;
private readonly CustomerBusinessService customerBusinessService;
public CustomerRepository(
AmounDB001DbContext _amounDB001DbContext,
CustomerBusinessService _customerBusinessService
)
{
this.amounDB001DbContext = _amounDB001DbContext;
customerBusinessService= _customerBusinessService;
}
public bool AddCustomer(Customers c)
{
if (c != null && customerBusinessService.CheckAllFields(c))
{
amounDB001DbContext.Add(c);
amounDB001DbContext.SaveChangesAsync();
return true;
}
return false;
}
public bool RemoveCustomer(Customers c)
{
if (c != null && customerBusinessService.CheckAllFields(c))
{
amounDB001DbContext.Customers.Remove(c);
amounDB001DbContext.SaveChanges();
return true;
}
return false;
}
public bool UpdateCustomer(Customers c)
{
if (c != null && customerBusinessService.CheckAllFields(c))
{
amounDB001DbContext.Customers.Update(c);
amounDB001DbContext.SaveChanges();
return true;
}
return false;
}
public List<Customers> GetAllCustomers()
{
return amounDB001DbContext.Customers.ToList();
}
public Customers GetCustomer(int customerID)
{
if (customerID == 0)
{
return null;
}
return amounDB001DbContext.Customers.FirstOrDefault(c => c.CustomerID == customerID);
}
}
}
I'm not sure what I'm doing wrong. Any ideas?

Answer 1

I think you should change the constructor of CustomerRepository, replacing the parameter type CustomerBusinessService with the interface you registered as a service ICustomerBusinessService.
public class CustomerRepository : ICustomerRepository
{
private readonly AmounDB001DbContext amounDB001DbContext;
private readonly ICustomerBusinessService customerBusinessService;
public CustomerRepository(
AmounDB001DbContext _amounDB001DbContext,
ICustomerBusinessService _customerBusinessService
)
{
this.amounDB001DbContext = _amounDB001DbContext;
customerBusinessService= _customerBusinessService;
}
...