The document describes how to build a Movie List application using ASP.NET MVC and Entity Framework Core by explaining how to set up the model classes, controllers, views, and database context to display, add, edit and delete movie data, relating movies to genres and making the URLs more user-friendly. It provides code examples for each part of the application.

1. CHAPTER 4
HOW TO DEVELOP A DATA-
DRIVEN MVC WEB APP
By : Eng. Mahmoud Hassouna
Email : M.hassuna2@gmail.com

2. How to start the Movie List app?
1. the Movie List page displays the movie data in a table
2. Above the table, the page displays a link that users can click when
they want to add a new movie.
3. Within the table, each row displays two links users can click when
they want to edit or delete an existing movie.

3. What happened If the user clicks the
Add New Movie link?
 The app displays the Add Movie page. This page
displays a form with text boxes that let the user enter
the name, year, and rating for a movie. In addition, it
displays a drop-down list that allows users to select a
genre for the movie.
 If the user clicks one of the Edit links in the table on the
Movie List page…
The app displays the Edit Movie page

4. What happened if the user clicks
one of the Delete links?
 The app displays the Delete Movie page.
 This page simply asks users to confirm that they really want to delete
the selected movie.
 If they do, they click the Delete button to delete the movie from the
database.
 If they don’t, they click the Cancel button to return the user to the
Movie List page.

5. The pages of the Movie List app

6. The folders and files of the app:
 The Solution Explorer contains:
1. Models
2. Views
3. Controllers folders

7. The Solution Explorer for the Movie
List app

8. Folders in the Movie List app

9. Files in the Movie List app

10. How to use EF Core:
 Entity Framework (EF) Core is an object-relational
mapping (ORM) framework that allows you to work with
the objects of a database in code. In the next few
figures, you’ll learn how to code classes that define the
structure of a database. Then, you’ll learn how to create
a database from this code.

11. How to add EF Core to your project:
 Prior to .NET Core 3.0, EF Core and the tools to work with it were
included with ASP.NET Core by default. However, with .NET Core 3.0
and later, you must manually add EF Core and the EF Core Tools to
your project. To do that with Visual Studio, you need to find and
install the correct NuGet packages.
Note:
If you try to install a version of EF Core or EF Core Tools that’s newer
than the version of .NET Core you installed, you might get errors.

12. How to open the NuGet Package
Manager?
Select Tools
Nuget Package
Manager
Manage Nuget
Package for
Solution

13. The NuGet Package Manager

14. How to install the EF Core and EF
Core Tools NuGet packages:
1. Click the Browse link in the upper left of the window.
2. Type “Microsoft.EntityFrameworkCore.SqlServer” in the search box.
3. Click on the appropriate package from the list that appears in the left-hand panel.
4. In the right-hand panel, check the project name, select the version that matches
the version of .NET Core you’re running, and click Install.
5. Review the Preview Changes dialog that comes up and click OK.
6. Review the License Acceptance dialog that comes up and click I Accept.
7. Type “Microsoft.EntityFrameworkCore.Tools” in the search box.
8. Repeat steps 3 through 6.

15. How to create a DbContext class
EF Code First:
The most common way to work with EF Core is to code your
model classes first. Then, you can use EF Core to generate a
database from those classes.
The DbContext class:
The primary class for communicating with a database.
The DbContextOptions class:
Provides configuration information to the DbContext class.

16. How to create a DbContext class
cont.
The DbSet class:
Represents a collection of model classes, also known as
entity classes, or domain model classes, that map to a
database table.

17. Three classes provided by EF Core

20. How to seed initial data
 One method of the DbContext class:

21. How to seed initial data cont.
-The MovieContext class updated to seed initial Movie data

22. How to add a connection string
 A connection string: is a string that specifies information
that an app needs to connect to a database or other
data source.
 To add a connection string, you can hard-code
connection strings in the code for your app, it’s generally
considered a best practice to store them in a
configuration file.

23. How to enable dependency injection
 Dependency injection: is a design pattern in which
the services an object needs are passed to it rather than
being hard coded as part of the object.
 Core MVC uses dependency injection to pass
DbContext objects to the controllers that need them.

24. A connection string in the
appsettings.json file:

25. Code that enables dependency
injection for DbContext objects:

26. How to use migrations to create the
database
 The Package Manager Console (PMC) window in Visual Studio

27. How to use migrations to create the
database cont.
How to open the Package Manager Console window:
Select the Tools
NutGet Package
Manager
Package Manager
Console command
How to create the Movies database based on your code files:
1. Make sure the connection string and dependency injection are set up.
2. Type “Add-Migration Initial” in the PMC at the command prompt and press Enter.
3. Type “Update-Database” at the command prompt and press Enter.

28. How to use migrations to create the
database cont.
 The code in the Up() method of the Initial migration file:

29. How to use migrations to create the
database cont.
 How to view the database once it’s created:
1. Choose the View SQL Server Object Explorer command in Visual Studio.
2. Expand the (localdb)MSSQLLocalDB node, then expand the Databases node.
3. Expand the Movies node, then expand the Tables node.
4. To view the table columns, expand a table node and then its Columns node.
5. To view the table data, right-click a table and select the ViewData command.

30. How to work with data
Work with Data
Select Data
Language-Intergrated
Query(LINQ)
Methods of
DbContext &
DbSet classes
Insert Update Delete

31. How to select Data
 Steps to using LINQ and EF Core to select data from a database:
1. build a query expression.
2. execute that query expression at the database.

32. How to select Data cont.
LINQ methods that build or execute a query expression

33. How to select Data cont.
A method of the DbSet class that gets an entity by its id

34. How to select Data cont.

35. How to select Data cont.

36. How to insert, update, and delete
data
 Three methods of the DbSet class
One method of the DbContext class

37. How to insert, update, and delete
data

38. How to insert, update, and delete
data

39. How to insert, update, and delete
data

40. The Movie List app
 The Home controller
 The Home/Index view

41. The Movie List app
 The Home controller
Figure starts by presenting the code for the Home controller of the
Movie List app. This controller starts with a private property named context of
the Movie Context type. Then, the constructor accepts a Movie Context object
and assigns it to the context property. As a result, the other methods in this class
can easily access the Movie Context object.
This constructor works because of the dependency injection code in the
Startup.cs file presented in figure 4-6. That’s because the constructor specifies
that it needs an instance of the MovieContext class. As a result, the MVC
framework creates one based on the options specified in the Startup.cs file and
passes it to that constructor.
The Index() action method of the Home controller uses the context property
to get a collection of Movie objects from the database. But first, it sorts those
objects alphabetically by movie name. Then, it passes that collection to the view.

42. The Movie List app
 The Home controller

43. The Movie List app
 The Home/Index view
This figure also presents the code for the Home/Index view of the Movie
List app. This view begins by using the @model directive to specify that the
model for this view is a collection of Movie objects because that’s what the
Index() action method of the Home controller passes to this view.
Most of the HTML in this view displays a table of movie data. Just above
the table, a link requests the Add() action method of the Movie controller. This
link allows the user to add a new movie.
Within the body of the table, an inline foreach statement loops through the
collection of Movie objects and displays each one in a row. Within that loop, the
fourth column adds links that request the Edit() and Delete() action methods of
the Movie controller for that specific movie. These links also use the asp-route-id
tag helper to pass the ID for each movie. You’ll learn more about how this tag
helper works in chapter 7. For now, all you need to know is that it appends the
MovieId value for the selected movie to the end of the URL.

44. The Movie List app
 The Home/Index view

45. The Movie List app
 The Movie controller
 Description
The Add() and Edit() action methods
both display the Movie/Edit view.

46. The Movie List app
 The Movie/Edit view

47. The Movie List app
 The Movie/Delete view

48. How to work with related data
 How to relate one entity to another

49. How to work with related data
 How to update the DbContext class and the seed data

50. How to work with related data
 How to use migrations to update the database

51. How to select related data and display it
on the Movie List page
 At this point, you’re ready to update the Movie List app so it displays this new
Genre data.
 The first example in this figure shows how to update the controller for the Movie
List page. To start, this controller adds a using directive for the EF Core
namespace. Then, the Index() action uses the Include() method of the EF Core
namespace to select the genre data related to each movie.
 The Include() method accepts a lambda expression that specifies the related entity.
Whenever necessary, you can chain the Include() method as part of a longer LINQ
query. Like the OrderBy() method, the Include() method doesn’texecute at the
database. Instead, it helps build up the query expression that theToList() method
eventually executes.

52.  If you only need the GenreId value, not the data for the entire entity, you don’t need
to use the Include() method. That’s because the Movie entity contains a foreign key
property named GenreId. In other words, the GenreId value is automatically
included when you select a Movie object. However, in this case, you want to get all
the Genre data, not just the GenreId value. As a result, you need to use Include().
 Once you’ve selected the related data, you use regular C# dot notation to work with
it. In the second example, for instance, the Home/Index view adds a Genre column
to the movie table. Within the foreach loop, it uses dot notation to display the Name
property of the Genre property of the Movie object.
How to select related data and display
it on the Movie List page

53. How to select related data and display
it on the Movie List page

54.  The Add() action method of the Movie controller
How to display related data on the
Add and Edit Movie pages
 The Edit() action method of the Movie controller for GET requests

55.  The Edit() action method of the Movie controller for POST requests
How to display related data on the
Add and Edit Movie pages

56.  How to make URLs lowercase with a trailing slash
How to make user-friendly URLs
By default, MVC uses the names of the controllers and their action
methods
to create the URLs of the app. By convention, these names begin with an
uppercase letter. This produces URLs that use some uppercase letters
like those
shown at the top of figure 4-19.
However, there’s also a convention that URLs should be lowercase. This
makes them easier for users to type. In addition, some developers like to
include
a trailing slash after a URL. This makes it easy for users to add text to
the end of
a URL.
Fortunately, it’s easy to make your MVC app produce URLs that are
lowercase and have a trailing slash. To do that, you just need to adjust
the

57.  The default URLs of an MVC app
How to make user-friendly URLs

58.  The same MVC pages after changing the URL configuration
How to make user-friendly URLs
 Description
• By default, MVC uses the names of the controllers and their action methods to
create the URLs of the app. By convention, these names begin with an uppercase
letter.
• It’s generally considered a good practice to use lowercase letters for URLs.
• Some developers like to include a trailing slash after each URL to make it easy for
users to type text at the end of a URL.

59. How to add a slug
 The Edit page with numeric ID values only in the URL

60. How to add a slug
 The Edit page after updating the code to add a slug to the URL
 Description
• A slug is a descriptive section at the end of a URL. You can add a
slug by adding an optional route parameter named slug to the
Startup.cs file, adding a Slug property to the entity class, and
including the Slug property on a link.

61. “
”
SOLVE THE EXERCISE 4-1 FROM
MURACH BOOK