An unhandled exception has occurred while executing the request.
System.InvalidOperationException: Unable to resolve service for type 'projetoweb.projetoContext' while attempting to activate 'projetoweb.Controllers.AnuncianteController'.
   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.<CreateActivator>b__0(ControllerContext controllerContext)
   at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.<CreateControllerFactory>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.Builder.RouterMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 74.3081ms 500 text/html; charset=utf-8

using System;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;
using projetoweb.Models;

namespace projetoweb
{
    public partial class projetoContext : DbContext
    {
         public DbSet<Anunciante> Anunciante { get; set; }
         public DbSet<Comprador> Comprador { get; set; }
         public DbSet<Pedido> Pedido { get; set; }
         public DbSet<Produto> Produto { get; set; }
         public DbSet<Promocao> Promocao { get; set; }

        public projetoContext()
        {
        }

        public projetoContext(DbContextOptions<projetoContext> options)
            : base(options)
        {
        }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
                optionsBuilder.UseMySql("Server=;Database=projeto;User=;Password=;");
            }
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {}
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using projetoweb;
using projetoweb.Models;

namespace projetoweb.Controllers
{
    public class AnuncianteController : Controller
    {
        private readonly projetoContext _context;

        public AnuncianteController(projetoContext context)
        {
            _context = context;
        }

        // GET: Anunciante
        public async Task<IActionResult> Index()
        {
            return View(await _context.Anunciante.ToListAsync());
        }

        // GET: Anunciante/Details/5
        public async Task<IActionResult> Details(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var anunciante = await _context.Anunciante
                .FirstOrDefaultAsync(m => m.anu_id == id);
            if (anunciante == null)
            {
                return NotFound();
            }

            return View(anunciante);
        }

        // GET: Anunciante/Create
        public IActionResult Create()
        {
            return View();
        }

        // POST: Anunciante/Create
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create([Bind("anu_id,anu_nome,anu_cpnj,anu_senha,anu_rua,anu_bairro,anu_cidade,anu_estado,anu_plano_atual,anu_qtd_anuncios,anu_qtd_anuncios_relevantes,anu_data_cadastro,anu_imagem")] Anunciante anunciante)
        {
            if (ModelState.IsValid)
            {
                _context.Add(anunciante);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            return View(anunciante);
        }

        // GET: Anunciante/Edit/5
        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var anunciante = await _context.Anunciante.FindAsync(id);
            if (anunciante == null)
            {
                return NotFound();
            }
            return View(anunciante);
        }

        // POST: Anunciante/Edit/5
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, [Bind("anu_id,anu_nome,anu_cpnj,anu_senha,anu_rua,anu_bairro,anu_cidade,anu_estado,anu_plano_atual,anu_qtd_anuncios,anu_qtd_anuncios_relevantes,anu_data_cadastro,anu_imagem")] Anunciante anunciante)
        {
            if (id != anunciante.anu_id)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(anunciante);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!AnuncianteExists(anunciante.anu_id))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }
            return View(anunciante);
        }

        // GET: Anunciante/Delete/5
        public async Task<IActionResult> Delete(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var anunciante = await _context.Anunciante
                .FirstOrDefaultAsync(m => m.anu_id == id);
            if (anunciante == null)
            {
                return NotFound();
            }

            return View(anunciante);
        }

        // POST: Anunciante/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            var anunciante = await _context.Anunciante.FindAsync(id);
            _context.Anunciante.Remove(anunciante);
            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        private bool AnuncianteExists(int id)
        {
            return _context.Anunciante.Any(e => e.anu_id == id);
        }
    }
}