Getting “Could not resolve a service of type ..” after upgrading to Core 2 Preview 2

[SteinTheRuler]

I've just upgraded to ASP.NET Core 2 Preview 2 and ran into a problem with the depedency injection. I get

Could not resolve a service of type 'LC.Tools.API.Data.GenericDbContext' for the parameter 'context' of
method 'Configure' on type 'LC.Tools.API.Startup'

when running/debugging the project.

I didn't have this problem using the old version.

DbContext (GenericDbContext):

    namespace LC.Tools.API.Data
    {
        public class GenericDbContext : DbContext
        {
            public GenericDbContext(DbContextOptions<GenericDbContext> options) : base(options) { }
    
            protected override void OnModelCreating(ModelBuilder builder)
            {
               //Generic
                builder.Entity<Client>();
                builder.Entity<Graphic>();
                        .
    			.
    			.
    			.
    			.
    
                //Shop
                builder.Entity<Models.Shop.Store>().ToTable("ShopClient");
                builder.Entity<Models.Shop.Category>().ToTable("ShopCategory");
    			.
    			.
    			.
    			.
    			.
    			.
    	}
    }

Startup.cs:

    namespace LC.Tools.API
    {
        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();
    
                this.HostingEnvironment = env;
            }
    
            public void ConfigureServices(IServiceCollection services)
            {
                services.AddOptions();
                services.AddDbContext<Data.GenericDbContext>(options => options.UseSqlServer(this.ConnectionString));
    
                services.AddMvc();
            }
    
            public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, Data.GenericDbContext context)
            {
                loggerFactory.AddConsole(Configuration.GetSection("Logging"));
                loggerFactory.AddDebug();
    
                if (env.IsDevelopment())
                {
                    app.UseForwardedHeaders(new ForwardedHeadersOptions
                    {
                        ForwardedHeaders = Microsoft.AspNetCore.HttpOverrides.ForwardedHeaders.XForwardedFor,
                        ForwardLimit = 2
                    });
    
                    app.UseDeveloperExceptionPage();
                    app.UseBrowserLink();
                }
    
                app.UseStaticFiles();
                app.UseMvc();
    
                Data.Debug.Init.Initalize(context, env);
            }
    
            private IHostingEnvironment HostingEnvironment { get; set; }
    
            public IConfigurationRoot Configuration { get; }
    
            private string ConnectionString
            {
                get
                {
                    return this.HostingEnvironment.IsDevelopment() ? Configuration.GetConnectionString("Development") : Configuration.GetConnectionString("Production");
                }
            }
        }
    }

Exception:

An error occurred while starting the application.

InvalidOperationException: Cannot resolve scoped service
'LC.Tools.API.Data.GenericDbContext' from root provider.

Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteValidator.ValidateResolution(Type
serviceType, ServiceProvider serviceProvider) Exception: Could not
resolve a service of type 'LC.Tools.API.Data.GenericDbContext' for the
parameter 'context' of method 'Configure' on type
'LC.Tools.API.Startup'.

Microsoft.AspNetCore.Hosting.Internal.ConfigureBuilder.Invoke(object
instance, IApplicationBuilder builder)

InvalidOperationException: Cannot resolve scoped service
'LC.Tools.API.Data.GenericDbContext' from root provider.

Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteValidator.ValidateResolution(Type
serviceType, ServiceProvider serviceProvider)
Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type
serviceType)
Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider
provider, Type serviceType)
Microsoft.AspNetCore.Hosting.Internal.ConfigureBuilder.Invoke(object instance, IApplicationBuilder builder)

[SteinTheRuler]

I solved it by using the following implementation:

        public IServiceProvider ConfigureServices(IServiceCollection services)
        {
            services.AddEntityFrameworkSqlServer()
                .AddOptions()
                .AddDbContext<Data.GenericDbContext>(options => options.UseSqlServer(this.ConnectionString));       

            services.AddMvc();

            var serviceProvider = services.BuildServiceProvider();

            return serviceProvider;
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IServiceProvider serviceProvider)
        {
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();

            if (env.IsDevelopment())
            {
                app.UseForwardedHeaders(new ForwardedHeadersOptions
                {
                    ForwardedHeaders = Microsoft.AspNetCore.HttpOverrides.ForwardedHeaders.XForwardedFor,
                    ForwardLimit = 2
                });

                app.UseDeveloperExceptionPage();
                app.UseBrowserLink();
            }

            app.UseStaticFiles();
            app.UseMvc();

            var dbContext = serviceProvider.GetService<Data.GenericDbContext>();
            Data.Debug.Init.Initalize(dbContext, env);
        }

[Tratcher]

FYI: I don't recommend running DB initialization in Configure in 2.0. As a side effect of some design changes, ef tooling like migrations now runs both ConfigureServices and Configure. You're better off moving this to Main. Guidance docs are in progress dotnet/AspNetCore.Docs#3864.

[aspnet-hello]

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