Styjun

When I try and access my repository, I receive an error:

InvalidOperationException: Unable to resolve service for type 'software.Notes.Repositories.NoteRepository' while attempting to activate 'software.Notes.Http.Handlers.ShowNote'.

So, I have a simple SoftwareContext:

using Microsoft.EntityFrameworkCore;
using software.Contacts.Entities;
using software.Notes.Entities;

namespace software.Core.Entities

 public class SoftwareContext : DbContext
 
 /// <inheritdoc />
 /// <summary>
 /// Constructor
 /// </summary>
 public SoftwareContext(DbContextOptions options)
 : base(options)
 

 /// <summary>
 /// Contact model
 /// </summary>
 public DbSet<Contact> Contact get; set; 

 /// <summary>
 /// Note model
 /// </summary>
 public DbSet<Note> Note get; set; 
 

which is instantiated in my startup.cs file:

services.AddDbContext<SoftwareContext>(options =>
 options.UseMySql(Configuration.GetConnectionString("DefaultConnection")));

Now, I have a simple request handler to show a note:

using Microsoft.AspNetCore.Mvc;
using software.Notes.Entities;
using software.Notes.Repositories;

namespace software.Notes.Http.Handlers

 [ApiController]
 public class ShowNote : Controller
 
 /// <summary>
 /// Note Repository
 /// </summary>
 private readonly NoteRepository _note;

 /// <summary>
 /// ShowNote constructor
 /// </summary>
 /// <param name="note"></param>
 public ShowNote(NoteRepository note)
 
 _note = note;
 

 /// <summary>
 /// Get the Note via the ID
 /// </summary>
 /// <param name="id"></param>
 /// <returns></returns>
 [HttpGet]
 [Route("note/show/id")]
 public IActionResult init(int id)
 
 Note note = _note.Find(id);

 if (note != null) 
 return Ok(note);
 

 return NotFound();
 
 

And inside my repository I have the following:

using System;
using System.Collections.Generic;
using System.Linq;
using software.Core.Entities;
using software.Notes.Entities;
using software.Notes.Repositories.Contracts;

namespace software.Notes.Repositories

 public abstract class NoteRepository : INoteRepository
 
 /// <summary>
 /// Database context
 /// </summary>
 private readonly SoftwareContext _context;

 /// <summary>
 /// Bind the database to the repo
 /// </summary>
 /// <param name="context"></param>
 protected NoteRepository(SoftwareContext context)
 
 _context = context;
 

 /// <summary>
 /// Create an item from the object
 /// </summary>
 /// <param name="note"></param>
 /// <returns></returns>
 public Note Create(Note note)
 
 var add = _context.Note.Add(note);

 return note;
 

 /// <summary>
 /// Find a note by the id
 /// </summary>
 /// <param name="id"></param>
 /// <returns></returns>
 public Note Find(int id)
 
 return _context.Note.FirstOrDefault(x => x.Id.Equals(id));
 
 

Shouldn't the Context be injected via the constructor of my repository like I am currently doing? Can someone explain why this isn't working, and what the correct way to do it for it to work would be?

Full exception log:

System.InvalidOperationException: Unable to resolve service for type 'software.Notes.Repositories.NoteRepository' while attempting to activate 'software.Notes.Http.Handlers.ShowNote'.
at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)
at lambda_method(Closure , IServiceProvider , Object[] )
at Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.<>c__DisplayClass4_0.b__0(ControllerContext controllerContext)
at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.g__CreateController|0(ControllerContext controllerContext)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync()
at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter()
at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()
at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync()
at Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext httpContext)
at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

You will have to add your NoteRepository inside the .NET Core’s IOC container. There are three ways to do that:
in the startup.cs class add

services.AddScoped<INoteRepository, NoteRepository>();

which will create instance of NoteRepository class once per request

services.AddSingleton <INoteRepository, NoteRepository>();

which mean instance of your NoteRepository class will be shared across requests

services.AddTransient <INoteRepository, NoteRepository>();

which will create the instance each time application request it.

then you can inject the dependency through constructor of your controller

 [ApiController]
 public class ShowNote : Controller
 
 private readonly INoteRepository _note;
 public ShowNote(INoteRepository note)
 
 _note = note;
 

maybe you need to pass the context to the dbcontextoptions in the constructor? So try change this:

public SoftwareContext(DbContextOptions options)
 : base(options)
 

to this:

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