Introduction:
This article will explain how to perform CRUD (Create, Read, Update and Delete) operations in ASP.NET Core Web API using Entity Framework Core. We will see step by step instructions about CRUD operations in ASP.NET Core Web API. In this demonstration, we will use the Database First Approach where our database will be ready before creating an actual code.
Prerequisites:
1. Visual Studio 2019.
2. Sql Server 2014.
Let's start practical demonstration, below code snippet is Employee Model class
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace DotNetCoreAPI.Models
{
public class Employee
{
public long Id { get; set; }
public string Name { get; set; }
public bool IsComplete { get; set; }
}
}
And create context class for Employee.
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace DotNetCoreAPI.Models
{
public class EmpContext : DbContext
{
public EmpContext(DbContextOptions<EmpContext> options)
:base(options)
{
}
public DbSet<Employee> Employees { get; set; }
}
}
Register database context.
In ASP.NET Core, services such as the DB context must be registered with the dependency injection (DI) container. The container provides the service to controllers.
Update Startup.cs with the following highlighted code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using DotNetCoreAPI.Models;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.EntityFrameworkCore;
namespace DotNetCoreAPI
{
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
string con = @"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=VijayDB;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False";
services.AddDbContext<EmpContext>(opt =>
opt.UseSqlServer(con));
services.AddControllers();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseHttpsRedirection();
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}
}
Right-click the Controllers folder.
Select Add > New Scaffolded Item.
Select API Controller with actions, using Entity Framework, and then select Add.
In the Add API Controller with actions, using Entity Framework dialog:
- Select TodoItem (TodoApi.Models) in the Model class.
- Select TodoContext (TodoApi.Models) in the Data context class.
- Select Add.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using DotNetCoreAPI.Models;
namespace DotNetCoreAPI.Controllers
{
[Route("api/[controller]")]
[ApiController]
public class EmployeesController : ControllerBase
{
private readonly EmpContext _context;
public EmployeesController(EmpContext context)
{
_context = context;
}
// GET: api/Employees
[HttpGet("EmployeeList")]
public async Task<ActionResult<IEnumerable<Employee>>> GetEmployees()
{
return await _context.Employees.ToListAsync();
}
// GET: api/Employees/5
[HttpGet("EmpById/{id}")]
public async Task<ActionResult<Employee>> GetEmployee(long id)
{
var employee = await _context.Employees.FindAsync(id);
if (employee == null)
{
return NotFound();
}
return employee;
}
// PUT: api/Employees/5
// To protect from overposting attacks, enable the specific properties you want to bind to, for
// more details, see https://go.microsoft.com/fwlink/?linkid=2123754.
[HttpPut("Update/{id}")]
public async Task<IActionResult> PutEmployee(long id, Employee employee)
{
if (id != employee.Id)
{
return BadRequest();
}
_context.Entry(employee).State = EntityState.Modified;
try
{
await _context.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!EmployeeExists(id))
{
return NotFound();
}
else
{
throw;
}
}
return NoContent();
}
// POST: api/Employees
// To protect from overposting attacks, enable the specific properties you want to bind to, for
// more details, see https://go.microsoft.com/fwlink/?linkid=2123754.
[HttpPost("Insert")]
public async Task<ActionResult<Employee>> PostEmployee(Employee employee)
{
_context.Employees.Add(employee);
await _context.SaveChangesAsync();
return CreatedAtAction(nameof(GetEmployee), new { id = employee.Id }, employee);
}
// DELETE: api/Employees/5
[HttpDelete("RemoveEmp/{id}")]
public async Task<ActionResult<Employee>> DeleteEmployee(long id)
{
var employee = await _context.Employees.FindAsync(id);
if (employee == null)
{
return NotFound();
}
_context.Employees.Remove(employee);
await _context.SaveChangesAsync();
return employee;
}
private bool EmployeeExists(long id)
{
return _context.Employees.Any(e => e.Id == id);
}
}
}
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