Duvidas DataService

insira seu código aqui

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.EntityFrameworkCore;

namespace CasaDoCodigo
{
    public class Startup
    {
        public Startup(IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                .AddEnvironmentVariables();
            Configuration = builder.Build();
        }

        public IConfigurationRoot Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            // Add framework services.
            services.AddMvc();
            string connectionString =
                Configuration.GetSection("ConnectionStrings")
                    .GetValue<string>("Default");
            services.AddDbContext<Contexto>(options => options.UseSqlServer(connectionString));

            services.AddTransient<IDataService, DataService>();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory,
            IServiceProvider serviceProvider)
        {
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();

            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseBrowserLink();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }

            app.UseStaticFiles();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Pedido}/{action=Carrossel}/{id?}");
            });

            IDataService dataService = serviceProvider
                .GetService<IDataService>();

            dataService.InicializaDB();
        }
    }
}

insira seu código aqui ```

Cara, organiza isso melhor, ficou uma bagunça, nao da nem pra entender. Usa o https://pasteboard.co/ para colocar as imagens e o trecho de codigo pra inserir as classes e a parte que gera erro dentro de um novo trecho de codigo separado

OK.......Melhor ?

Entao, parece que é um problema com sua connectionString ne vei, o nome esta o mesmo ?

Poe o web.config ae

insira seu código aqui
```Não tem arquivo chamado web.conf. Tem o arquivo appsettings.json.

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appsettings.json. 
{
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "ConnectionString": {
    "Default": "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=CasaDoCodigo;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=True;ApplicationIntent=ReadWrite;MultiSubnetFailover=False"

  }
}

insira seu código aqui ```

Olha esse trecho, esta no plural, e na definição esta no singular, não seria isso ? Configuration.GetSection("ConnectionStrings")

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```Correto Renan fazendo dessa forma apareceu outro exception segue:

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An error occurred while starting the application.
InvalidOperationException: A parameterless constructor was not found on entity type 'Produto'. In order to create an instance of 'Produto' EF requires that a parameterless constructor be declared.
Microsoft.EntityFrameworkCore.Metadata.Internal.EntityMaterializerSource.CreateMaterializeExpression(IEntityType entityType, Expression valueBufferExpression, Int32[] indexMap)
InvalidOperationException: A parameterless constructor was not found on entity type 'Produto'. In order to create an instance of 'Produto' EF requires that a parameterless constructor be declared.
Microsoft.EntityFrameworkCore.Metadata.Internal.EntityMaterializerSource.CreateMaterializeExpression(IEntityType entityType, Expression valueBufferExpression, Int32[] indexMap)
Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.MaterializerFactory.CreateMaterializer(IEntityType entityType, SelectExpression selectExpression, Func<IProperty, SelectExpression, int> projectionAdder, IQuerySource querySource)
Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.RelationalEntityQueryableExpressionVisitor.CreateShaper(Type elementType, IEntityType entityType, SelectExpression selectExpression)
Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.RelationalEntityQueryableExpressionVisitor.VisitEntityQueryable(Type elementType)
System.Linq.Expressions.ConstantExpression.Accept(ExpressionVisitor visitor)
Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.ExpressionVisitorBase.Visit(Expression node)
Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.ReplaceClauseReferences(Expression expression, IQuerySource querySource, bool inProjection)
Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor.CompileMainFromClauseExpression(MainFromClause mainFromClause, QueryModel queryModel)
Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.VisitMainFromClause(MainFromClause fromClause, QueryModel queryModel)
Remotion.Linq.QueryModelVisitorBase.VisitQueryModel(QueryModel queryModel)
Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.VisitQueryModel(QueryModel queryModel)
Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor.VisitQueryModel(QueryModel queryModel)
Microsoft.EntityFrameworkCore.Query.Internal.SqlServerQueryModelVisitor.VisitQueryModel(QueryModel queryModel)
Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.CreateQueryExecutor<TResult>(QueryModel queryModel)
Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.CompileQueryCore<TResult>(Expression query, INodeTypeProvider nodeTypeProvider, IDatabase database, ILogger logger, Type contextType)
Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler+<>c__DisplayClass19_0.<CompileQuery>b__0()
Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQueryCore<TFunc>(object cacheKey, Func<Func<QueryContext, TFunc>> compiler)
Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute<TResult>(Expression query)
System.Linq.Queryable.Count<TSource>(IQueryable<TSource> source)
CasaDoCodigo.DataService.InicializaDB() in DataService.cs
+
            if (this._contexto.Produtos.Count() == 0)
CasaDoCodigo.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IServiceProvider serviceProvider) in Startup.cs
+
            dataService.InicializaDB();
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
Microsoft.AspNetCore.Hosting.ConventionBasedStartup.Configure(IApplicationBuilder app)
Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()

Show raw exception details 
.NET Core X64 v4.1.1.0    |   Microsoft.AspNetCore.Hosting version 1.1.2    |    Microsoft Windows 10.0.15063    |   Need help?

insira seu código aqui ```

problema na sua classe produto vey, ela precisa de um cosntrutor padrao definido

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```Assim ??

insira seu código aqui

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace CasaDoCodigo.Models
{
    public class Produto
    {
        public int Id { get; private set; }
        public string Nome { get; private set; }
        public decimal Preco { get; private set; }

        //Construtor
        public Produto(int id, string nome, decimal preco) : this(nome, preco)
        {
            this.Id = id;

        }

        public Produto(string nome, decimal preco)
        {
            this.Nome = nome;
            this.Preco = preco;
        }
    }
}

insira seu código aqui ```

Na classe Produto adicionei esse metado Produto vazio antes do construtor.

public Produto() {

}

funcionou perfeitamente. Valeu !!