Using ASP.NET Core, Entity Framework Core and ASP.NET Boilerplate to Create NLayered Web Application (Part I)




This is first part of the “Using ASP.NET Core, Entity Framework Core and ASP.NET Boilerplate to Create NLayered Web Application” article series. See other parts:

In this article, I’ll show to create a simple cross platform layered web application using the following tools:

I will also use Log4Net and AutoMapper which are included in ABP startup template by default. We will use the following techniques:

The project will be developed here is a simple task management application where tasks can be assigned to people. Instead of developing the application layer by layer, I will go to vertical and change the layers as the application grows. While the application grows, I will introduce some features of ABP and other frameworks as needed.


Following tools should be installed in your machine to be able to run/develop the sample application:

  • Visual Studio 2017
  • SQL Server (you can change connection string to localdb)
  • Visual Studio Extensions:

Create the Application

I used ABP’s startup template ( to create a new web application named “Acme.SimpleTaskApp“. Company name (“Acme” here) is optional while creating templates. I also selected Multi Page Web Application since I don’t want to use SPA in this article and I disabled Include module zero since I want the most basic startup template:

Template creation aspnetboilerplate

It creates a layered solution as shown below: 

Startup template projects

It includes 6 projects starting with the name that I entered as the project name:

  • .Core project is for domain/business layer (entities, domain services…)
  • .Application project is for application layer (DTOs, application services…)
  • .EntityFramework project is for EF Core integration (abstracts EF Core from other layers).
  • .Web project is for ASP.NET MVC layer.
  • .Tests project is for unit and integration tests (up to application layer, excluding web layer)
  • .Web.Tests project is for ASP.NET Core integrated tests (complete integration test including the web layer).

When you run the application, you can see the user interface of the template:

Template Home Page

It contains a top menu, empty Home and About pages and a language switch dropdown.

Developing the Application

Creating a Task Entity

I want to start with a simple Task entity. Since an entity is part of the domain layer, I added it into the .Core project:

using System; using System.ComponentModel.DataAnnotations; using System.ComponentModel.DataAnnotations.Schema; using Abp.Domain.Entities; using Abp.Domain.Entities.Auditing; using Abp.Timing; namespace Acme.SimpleTaskApp.Tasks { [Table("AppTasks")] public class Task : Entity, IHasCreationTime { public const int MaxTitleLength = 256; public const int MaxDescriptionLength = 64 * 1024; [Required] [MaxLength(MaxTitleLength)] public string Title { get; set; } [MaxLength(MaxDescriptionLength)] public string Description { get; set; } public DateTime CreationTime { get; set; } public TaskState State { get; set; } public Task() { CreationTime = Clock.Now; State = TaskState.Open; } public Task(string title, string description = null) : this() { Title = title; Description = description; } } public enum TaskState : byte { Open = 0, Completed = 1 } }
  • I derived from ABP’s base Entity class, which includes Id property as int by default. We can use the generic version, Entity, to choice a different PK type.
  • IHasCreationTime is a simple interface just defines CreationTime property (it’s good to use a standard name for CreationTime).
  • Task entity defines a required Title and an optional Description.
  • TaskState is a simple enum to define states of a Task.
  • Clock.Now returns DateTime.Now by default. But it provides an abstraction, so we can easily switch to DateTime.UtcNow in the feature if it’s needed. Always use Clock.Now instead of DateTime.Now while working with ABP framework.
  • I wanted to store Task entities into AppTasks table in the database.

Adding Task to DbContext

.EntityFrameworkCore project includes a pre-defined DbContext. I should add a DbSet for the Task entity into the DbContext:

public class SimpleTaskAppDbContext : AbpDbContext { public DbSet Tasks { get; set; } public SimpleTaskAppDbContext(DbContextOptions options) : base(options) { } }

Now, EF Core knows that we have a Task entity. 

Creating the First Database Migration 

We will create an initial database migration to create database and the AppTasks table. I open the Package Manager Console from Visual Studio and run the Add-Migration command (Default project must be the .EntityFrameworkCore project):

Entity Framework Core Add Migration

This command creates a Migrations folder in the .EntityFrameworkCore project which includes a migration class and a snapshot of our database model:

EF Core initial migration

Automatically generated “Initial” migration class is shown below:

public partial class Initial : Migration { protected override void Up(MigrationBuilder migrationBuilder) { migrationBuilder.CreateTable( name: "AppTasks", columns: table => new { Id = table.Column(nullable: false) .Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn), CreationTime = table.Column(nullable: false), Description = table.Column(maxLength: 65536, nullable: true), State = table.Column(nullable: false), Title = table.Column(maxLength: 256, nullable: false) }, constraints: table => { table.PrimaryKey("PK_AppTasks", x => x.Id); }); } protected override void Down(MigrationBuilder migrationBuilder) { migrationBuilder.DropTable( name: "AppTasks"); } }

This code is used to create AppTasks table when we execute the migrations to the database (see entity framework documentation for more information on migrations).

Creating the Database

To create the database, I run Update-Database command from Package Manager Console:

EF Update-Database command

This command created a database named SimpleTaskAppDb in the local SQL Server and executed migrations (currently, there is a single, “Initial”, migration):

Created Database

Now, I have a Task entity and corresponding table in the database.  I entered a few sample Tasks to the table:

AppTasks table

Note that, the database connection string is defined in appsettings.json in the .Web application.

Task Application Service

Application Services are used to expose domain logic to the presentation layer. An Application Service is called from presentation layer with a Data Transfer Object (DTO) as parameter (if needed), uses domain objects to perform some specific business logic and returns a DTO back to the presentation layer (if needed).

I’m creating the first application service, TaskAppService, into the .Application project to perform task related application logic. First, I wanted to define an interface for the app service:

public interface ITaskAppService : IApplicationService { Task<ListResultOutput> GetAll(GetAllTasksInput input); }

Defining an interface is not required, but suggested. By convention, all app services should implement IApplicationService interface in ABP (it’s just an empty marker interface). I created a GetAll method to query tasks. To do that, I also defined the following DTOs:

public class GetAllTasksInput { public TaskState? State { get; set; } } [AutoMapFrom(typeof(Task))] public class TaskListDto : EntityDto, IHasCreationTime { public string Title { get; set; } public string Description { get; set; } public DateTime CreationTime { get; set; } public TaskState State { get; set; } }
  • GetAllTasksInput DTO defines input parameters of the GetAll app service method. Instead of directly defining the state as method parameter, I added it into a DTO object. Thus, I can add other parameters into this DTO later without breaking my existing clients (we could directly add a state parameter to the method).
  • TaskListDto is used to return a Task data. It’s derived from EntityDto, which just defines an Id property (we could add Id to our Dto and not derive from EntityDto). We defined [AutoMapFrom] attribute to create AutoMapper mapping from Task entity to TaskListDto. This attribute is defined in Abp.AutoMapper nuget package.
  • Lastly, ListResultOutput is a simple class contains a list of items (we could directly return a List).

Now, we can implement the ITaskAppService as shown below:

using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Abp.Application.Services.Dto; using Abp.Domain.Repositories; using Abp.Linq.Extensions; using Acme.SimpleTaskApp.Tasks.Dtos; using Microsoft.EntityFrameworkCore; namespace Acme.SimpleTaskApp.Tasks { public class TaskAppService : SimpleTaskAppAppServiceBase, ITaskAppService { private readonly IRepository _taskRepository; public TaskAppService(IRepository taskRepository) { _taskRepository = taskRepository; } public async Task<ListResultOutput> GetAll(GetAllTasksInput input) { var tasks = await _taskRepository .GetAll() .WhereIf(input.State.HasValue, t => t.State == input.State.Value) .OrderByDescending(t => t.CreationTime) .ToListAsync(); return new ListResultOutput( ObjectMapper.Map<List>(tasks) ); } } }
  • TaskAppService is derived from SimpleTaskAppAppServiceBase included in the startup template (which is derived from ABP’s ApplicationService class). This is not required, app services can be plain classes. But ApplicationService base class has some pre-injected services (like ObjectMapper used here).
  • I used dependency injection to get a repository.
  • Repositories are used to abstract database operations for entities. ABP creates a pre-defined repository (like IRepository here) for each entity to perform common tasks. IRepository.GetAll() used here returns an IQueryable to query entities.
  • WhereIf is an extension method of ABP to simplify conditional usage of IQueryable.Where method.
  • ObjectMapper (which somes from the ApplicationService base class and implemented via AutoMapper by default) is used to map list of Task objects to list of TaskListDtos objects.

Testing the TaskAppService

Before going further to create user interface, I want to test TaskAppService. You can skip this section if you don’t interest in automated testing.

Startup template contains .Tests project to test our code. It uses EF Core’s InMemory database provider instead of SQL Server. Thus, our unit tests can work without a real database. It creates a separated database for each test. Thus, tests are isolated from each other. We can use TestDataBuilder class to add some initial test data to InMemory database before running tests. I changed TestDataBuilder as shown below:

public class TestDataBuilder { private readonly SimpleTaskAppDbContext _context; public TestDataBuilder(SimpleTaskAppDbContext context) { _context = context; } public void Build() {  _context.Tasks.AddRange( new Task("Follow the white rabbit", "Follow the white rabbit in order to know the reality."), new Task("Clean your room") { State = TaskState.Completed } ); } }

You can see the sample project’s source code to understand where and how TestDataBuilder is used. I added two tasks (one of them is completed) to the dbcontext. So, I can write my tests assuming that there are two Tasks in the database. My first integration test tests the TaskAppService.GetAll method we created above.

public class TaskAppService_Tests : SimpleTaskAppTestBase { private readonly ITaskAppService _taskAppService; public TaskAppService_Tests() { _taskAppService = Resolve(); } [Fact] public async System.Threading.Tasks.Task Should_Get_All_Tasks() { var output = await _taskAppService.GetAll(new GetAllTasksInput()); output.Items.Count.ShouldBe(2); } [Fact] public async System.Threading.Tasks.Task Should_Get_Filtered_Tasks() { var output = await _taskAppService.GetAll(new GetAllTasksInput { State = TaskState.Open }); output.Items.ShouldAllBe(t => t.State == TaskState.Open); } }

I created two different tests to test GetAll method as shown above. Now, I can open Test Explorer (from Test\Windows\Test Explorer in the main menu of VS) and run the unit tests:

Test explorer

All of them succeed. The last one was a pre-built test in the startup template, which we can ignore for now.

Notice that; ABP startup template comes with xUnit and Shouldly installed by default. So, we used them to write our tests.

Task List View

Now, I know that TaskAppService is properly working. I can start to create a page to list all tasks.

Adding a New Menu Item

 First, I’m adding a new item to the top menu:

public class SimpleTaskAppNavigationProvider : NavigationProvider { public override void SetNavigation(INavigationProviderContext context) { context.Manager.MainMenu .AddItem( new MenuItemDefinition( "Home", L("HomePage"), url: "", icon: "fa fa-home" ) ).AddItem( new MenuItemDefinition( "About", L("About"), url: "Home/About", icon: "fa fa-info" ) ).AddItem( new MenuItemDefinition( "TaskList", L("TaskList"), url: "Tasks", icon: "fa fa-tasks" ) ); } private static ILocalizableString L(string name) { return new LocalizableString(name, SimpleTaskAppConsts.LocalizationSourceName); } }

Startup template comes with two pages: Home and About, as shown above. We can change them or create new pages. I prefered to leave them for now and create a new menu item.

Creating the TaskController and ViewModel

I’m creating a new controller class, TasksController, in the .Web project as shown below:

public class TasksController : SimpleTaskAppControllerBase { private readonly ITaskAppService _taskAppService; public TasksController(ITaskAppService taskAppService) { _taskAppService = taskAppService; } public async Task Index(GetAllTasksInput input) { var output = await _taskAppService.GetAll(input); var model = new IndexViewModel(output.Items); return View(model); } }
  • I derived from SimpleTaskAppControllerBase (which is derived from AbpController) that contains common base code for Controllers in this application.
  • I injected ITaskAppService in order to get list of tasks.
  • Instead of directly passing result of the GetAll method to the view, I created an IndexViewModel class in the .Web project which is shown below:
public class IndexViewModel { public IReadOnlyList Tasks { get; } public IndexViewModel(IReadOnlyList tasks) { Tasks = tasks; } public string GetTaskLabel(TaskListDto task) { switch (task.State) { case TaskState.Open: return "label-success"; default: return "label-default"; } } }

This simple view model gets a list of tasks (which is provided from ITaskAppService) in it’s constructor. It also has GetTaskLabel method that will be used in the view to select a Bootstrap label class for given task.

Task List Page

And finally, the Index view is shown below:

@model Acme.SimpleTaskApp.Web.Models.Tasks.IndexViewModel @{ ViewBag.Title = L("TaskList"); ViewBag.ActiveMenu = "TaskList"; //Matches with the menu name in SimpleTaskAppNavigationProvider to highlight the menu item } <h2>@L("TaskList")</h2> <div class="row"> <div> <ul class="list-group"> @foreach (var task in Model.Tasks) { <li class="list-group-item"> <span class="pull-right label @Model.GetTaskLabel(task)">@L($"TaskState_{task.State}")</span> <h4 class="list-group-item-heading">@task.Title</h4> <div class="list-group-item-text"> @task.CreationTime.ToString("yyyy-MM-dd HH:mm:ss") </div> </li> } </ul> </div> </div>

We simply used given model to render the view using Bootstrap’s list group component. Here, we used IndexViewModel.GetTaskLabel() method to get label types for tasks. Rendered page will be like that:

Task list


We used L method in the view which comes from ABP framework. It’s used to localize strings. We have define localized strings in Localization/Source folder in the .Core project as .json files. English localization is shown below:

{ "culture": "en", "texts": { "HelloWorld": "Hello World!", "ChangeLanguage": "Change language", "HomePage": "HomePage", "About": "About", "Home_Description": "Welcome to SimpleTaskApp...", "About_Description": "This is a simple startup template to use ASP.NET Core with ABP framework.",  "TaskList": "Task List", "TaskState_Open": "Open", "TaskState_Completed": "Completed" } }

Most of the texts are coming from startup template and can be deleted. I just added the last 3 lines and used in the view above. While using ABP’s localization is pretty simple, you can see localization document for more information on the localization system.

Filtering Tasks

As shown above, TaskController actually gets a GetAllTasksInput that can be used to filter tasks. So, we can add a dropdown to task list view to filter tasks. First, I added the dropdown to the view (I added inside the header):

<h2> @L("TaskList")  <span class="pull-right"> @Html.DropDownListFor( model => model.SelectedTaskState, Model.GetTasksStateSelectListItems(LocalizationManager), new { @class = "form-control", id = "TaskStateCombobox" }) </span> </h2>

Then I changed IndexViewModel to add SelectedTaskState property and GetTasksStateSelectListItems method:

public class IndexViewModel { public TaskState? SelectedTaskState { get; set; }  public List GetTasksStateSelectListItems(ILocalizationManager localizationManager) { var list = new List { new SelectListItem { Text = localizationManager.GetString(SimpleTaskAppConsts.LocalizationSourceName, "AllTasks"), Value = "", Selected = SelectedTaskState == null } }; list.AddRange(Enum.GetValues(typeof(TaskState)) .Cast() .Select(state => new SelectListItem { Text = localizationManager.GetString(SimpleTaskAppConsts.LocalizationSourceName, $"TaskState_{state}"), Value = state.ToString(), Selected = state == SelectedTaskState }) ); return list; } }

We should set SelectedTaskState in the controller:

public async Task Index(GetAllTasksInput input) { var output = await _taskAppService.GetAll(input); var model = new IndexViewModel(output.Items) { SelectedTaskState = input.State }; return View(model); }

Now, we can run the application to see the combobox at the top right of the view:

Task list

I added the combobox but it can not work yet. I’ll write a simple javascript code to re-request/refresh task list page when combobox value changes. So, I’m creating wwwroot\js\views\tasks\index.js file in the .Web project:

(function ($) { $(function () { var _$taskStateCombobox = $('#TaskStateCombobox');  _$taskStateCombobox.change(function() { location.href = '/Tasks?state=' + _$taskStateCombobox.val(); }); }); })(jQuery);

Before including this javascript file into my view, I used Bundler & Minifier VS extension (which is default way of minifying files in ASP.NET Core projects) to minify the script:

Minify js

This adds the following lines into bundleconfig.json file in the .Web project:

{ "outputFileName": "wwwroot/js/views/tasks/index.min.js", "inputFiles": [ "wwwroot/js/views/tasks/index.js" ] }

And creates a minified version of the script:

Minified js file

Whenever I change the index.js, index.min.js is automatically re-generated. Now, I can include the javascript file into my page:

@section scripts { <environment names="Development"> <script src="~/js/views/tasks/index.js"></script> </environment> <environment names="Staging,Production"> <script src="~/js/views/tasks/index.min.js"></script> </environment> }

With this code, our view will use index.js in development and index.min.js (minified version) in production. This is a common approach in ASP.NET Core MVC projects.

Automated Testing Task List Page

We can create integration tests that is also integrated to ASP.NET Core MVC infrastructure. Thus, we can completely test our server side code. You can skip this section if you don’t interest in automated testing.

ABP startup template includes a .Web.Tests project to do that. I created a simple test to request to TaskController.Index and check the response:

public class TasksController_Tests : SimpleTaskAppWebTestBase { [Fact] public async System.Threading.Tasks.Task Should_Get_Tasks_By_State() { var response = await GetResponseAsStringAsync( GetUrl(nameof(TasksController.Index), new { state = TaskState.Open } ) ); response.ShouldNotBeNullOrWhiteSpace(); } }

GetResponseAsStringAsync and GetUrl methods are some helper methods provided by AbpAspNetCoreIntegratedTestBase class of ABP. We can instead directly use the Client (an instance of HttpClient) property to make requests. But using these shortcut methods makes it easier. See integration testing documentation of ASP.NET Core for more.

When I debug the test, I can see the response HTML:

Web test

That shows the Index page returned a response without any exception. But… we may want to go more and check if returned HTML is what we expect. There are some libraries can be used to parse HTML. AngleSharp is one of them and comes as pre-installed in ABP startup template’s .Web.Tests project. So, I used it to check the created HTML code:

public class TasksController_Tests : SimpleTaskAppWebTestBase { [Fact] public async System.Threading.Tasks.Task Should_Get_Tasks_By_State() { var response = await GetResponseAsStringAsync( GetUrl(nameof(TasksController.Index), new { state = TaskState.Open } ) ); response.ShouldNotBeNullOrWhiteSpace();  var tasksInDatabase = await UsingDbContextAsync(async dbContext => { return await dbContext.Tasks .Where(t => t.State == TaskState.Open) .ToListAsync(); }); var document = new HtmlParser().Parse(response); var listItems = document.QuerySelectorAll("#TaskList li"); listItems.Length.ShouldBe(tasksInDatabase.Count); foreach (var listItem in listItems) { var header = listItem.QuerySelector(".list-group-item-heading"); var taskTitle = header.InnerHtml.Trim(); tasksInDatabase.Any(t => t.Title == taskTitle).ShouldBeTrue(); } } }

You can check the HTML deeper and in more detailed. But in most cases, checking the fundamental tags will be enough.


Second article continues developing this application.

Article History

  • 2017-06-02: Changed article and solution to support .net core.
  • 2016-08-08: Added link to the second article.
  • 2016-08-01: Initial publication.