AspDotNet.CRUD.LabExercise

Task

Create an ASP .NET App that enables CRUD Operation for the Customer Database.

Customer Entity Code

public class Customer
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string? Address { get; set; }
    public string? Phone { get; set; }
}

Solution Name: AspDotNet.CRUD.LabExercise

Project Folders

• CustomerData
• CustomerWeb

Create Models folder under CustomerData project

Create a BaseEntity class under Models folder

Import the following namespaces:

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

Under namespace CustomerData.Models, create a public abstract class BaseEntity

public abstract class BaseEntity
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }
    }

Create a Customer class under Models folder

Under namespace CustomerData.Models, create a public class Customer

public class Customer : BaseEntity
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string? Address { get; set; }
        public string? Phone { get; set; }
    }

Create Context folder under CustomerData project

Create CustomerDbContext class under Context folder

Import the following namespaces:

using CustomerData.Models;
using Microsoft.EntityFrameworkCore;

Create a public class CustomerDbContext that derives from DbContext Class

public class CustomerDbContext : DbContext
    {
        private readonly string _connectionString;
        public CustomerDbContext() : this(
            "Server = DESKTOP-47CLFBT; " +
            "Database = CustomerDb; " +
            "User Id = sa; " +
            "Password = D@gisik@n1997*")
        {

        }
        public CustomerDbContext(string connectionString)
        {
            this._connectionString = connectionString;
        }
        public DbSet<Customer> Customers { get; set; }
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
                optionsBuilder.UseSqlServer(this._connectionString);
            }
        }
    }

Generate Customer Database

Through the Package Manager Console, Enter Add-Migration [Insert any name] command to create Migrations folder. Then, use the command Update-Database to update the Database.

Create a Repository Folder that creates an abstraction layer between the data access layer and the business logic layer of an application.

Create a GenericRepository and a CustomerRepository class under the Repository folder

Generic Repository

Import the following namespaces:

using CustomerData.Context;
using CustomerData.Models;
using Microsoft.EntityFrameworkCore;

Create a public interface IBaseRepository<T> where the entity derives from the BaseEntity class

public interface IBaseRepository<T> where T : BaseEntity
    {
        IEnumerable<T> FindAll();
        T FindByPrimaryKey(int id);
        T Insert(T entity);
        T Update(T entity);
        T Delete(int id);
    }

Create public class GenericRepository<T> where the entity also derives from the BaseEntity class

public class GenericRepository<T> where T : BaseEntity
    {
    }

Under the GenericRepository<T> class, create the constructor with the parameter CustomerDbContext context

public GenericRepository(CustomerDbContext context)
        {
            this.Context = context;
        }

Create a property Context with type CustomerDbContext

public CustomerDbContext Context { get; set; }

Create a the following methods

1. FindAll() Displays all data from the database.

public IEnumerable<T> FindAll()
        {
            IQueryable<T> query = this.Context.Set<T>();
            return query.Select(c => c).ToList();
        }

2. FindByPrimaryKid(int id) Looks for a data in the database given an id.

 public T FindByPrimaryKey(int id)
        {
            var entity = this.Context.Find<T>(id);
            if (entity is object)
            {
                this.Context.Entry<T>(entity).State = EntityState.Detached;
                return entity;
            }
            throw new Exception($"Entity with ID {id} was not found.");
        }

3. Insert(T entity) Inserts a data to the database.

public T Insert(T entity)
        {
            Context.Add<T>(entity);
            Context.SaveChanges();
            return entity;
        }

4. Update(T entity) Updates a data from the database.

public T Update(T entity)
        {
            this.Context.Attach<T>(entity);
            this.Context.Entry(entity).State = EntityState.Modified;
            this.Context.SaveChanges();
            return entity;
        }

5. Delete(int id) Deletes data from the database.

public T Delete(int id)
        {
            var entity = this.FindByPrimaryKey(id);
            this.Context.Remove<T>(entity);
            this.Context.SaveChanges();
            return entity;
        }

Customer Repository