ASP.NET WEB API With Entity Framework 6 Code First Technique

Before proceeding to this article, please go through my previous articles:

In this article we are going to learn how to call ASP.NET WEB API from .NET Application.

Create One Employee model class in the project

public class Employee
{
[Key]
public int EmployeeId
{
get;
set;
}
public string FirstName
{
get;
set;
}
public string LastName
{
get;
set;
}
public int Age
{
get;
set;
}
}

Create a Context class in the project:

public class CRUDAPIContext : DbContext
{
public CRUDAPIContext() : base("name=CRUDAPIContext")
{
}
public System.Data.Entity.DbSet<CRUDAPI.Models.Employee> Employees { get; set; }
}

The Employees Controller class

public class EmployeesController : ApiController
{
private CRUDAPIContext db = new CRUDAPIContext();
// GET: api/Employees
public IQueryable<Employee> GetEmployees()
{
return db.Employees;
}
// GET: api/Employees/5
[ResponseType(typeof(Employee))]
public async Task<IHttpActionResult> GetEmployee(int id)
{
Employee employee = await db.Employees.FindAsync(id);
if (employee == null)
{
return NotFound();
}
return Ok(employee);
}
// PUT: api/Employees/5
[ResponseType(typeof(void))]
public async Task<IHttpActionResult> PutEmployee(int id, Employee employee)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (id != employee.EmployeeId)
{
return BadRequest();
}
db.Entry(employee).State = EntityState.Modified;
try
{
await db.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!EmployeeExists(id))
{
return NotFound();
}
else
{
throw;
}
}
return StatusCode(HttpStatusCode.OK);
}
// POST: api/Employees
[ResponseType(typeof(Employee))]
public async Task<IHttpActionResult> PostEmployee(Employee employee)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
db.Employees.Add(employee);
await db.SaveChangesAsync();
return CreatedAtRoute("DefaultApi", new { id = employee.EmployeeId }, employee);
}
// DELETE: api/Employees/5
[ResponseType(typeof(Employee))]
public async Task<IHttpActionResult> DeleteEmployee(int id)
{
Employee employee = await db.Employees.FindAsync(id);
if (employee == null)
{
return NotFound();
}
db.Employees.Remove(employee);
await db.SaveChangesAsync();
return Ok(employee);
}
}
}

SQL Table

Our API’s are ready, so now we can call these API from the .NET Application. In my case I’m taking a console Application.

Create one console Application:

Installing the WEB API Client libraries:

Use NuGet Package Manager to install the Web API Client Libraries package for Console Application or else use Install –Package Microsoft.AspNet.WebApi.Client command in package manager console.

Create a Model class in Console Application

public class Employee
{
public int EmployeeId
{
get;
set;
}
public string FirstName
{
get;
set;
}
public string LastName
{
get;
set;
}
public int Age
{
get;
set;
}
}

Call GetEmployees API Action from Console Application using HTTP Client

HTTP Client:

It is a class which is from System.Net.Http Namespace and provides a base class for sending HTTP requests and receiving HTTP responses from a resource identified by a URI.

Example

class Program
{
static void Main(string[] args)
{
ApiCall().Wait();
}
static async Task ApiCall()
{
using (var client = new HttpClient())
{
HttpResponseMessage response = client.GetAsync("http://localhost:57135/api/Employees/1").Result;
if (response.IsSuccessStatusCode)
{
Employee emp = await response.Content.ReadAsAsync<Employee> ();
Console.WriteLine("{0}\t{1}\t{2}\t{3}", emp.EmployeeId, emp.FirstName, emp.LastName, emp.Age);
Console.ReadKey();
}
}
}
}

Result

Call Employees POST API Action

class Program
{
static void Main(string[] args)
{
ApiCall();
}
static void ApiCall()
{
using (var client = new HttpClient())
{
//HTTP POST
var addEmp = new Employee() { FirstName = "John", LastName = "Miller", Age = 25 };
HttpResponseMessage response = client.PostAsJsonAsync("http://localhost:57135/api/Employees", addEmp).Result;
Console.WriteLine("{0}\t{1}", "StatusCode:", response.StatusCode);
Console.ReadKey();
}
}
}

Result

Reflection in SQL Table

Call Employees PUT API Action

class Program
{
static void Main(string[] args)
{
ApiCall();
}
static void ApiCall()
{
using (var client = new HttpClient())
{
//HTTP PUT
var updateEmp = new Employee() {EmployeeId=3, FirstName = "John", LastName = "Miller", Age = 27 };
HttpResponseMessage response = client.PutAsJsonAsync("http://localhost:57135/api/Employees/3", updateEmp).Result;
Console.WriteLine("{0}\t{1}", "StatusCode:", response.StatusCode);
Console.ReadKey();
}
}
}

Result

Reflection in SQL Table

Call Employees Delete API Action

class Program
{
static void Main(string[] args)
{
ApiCall();
}
static void ApiCall()
{
using (var client = new HttpClient())
{
//HTTP DELETE
HttpResponseMessage response = client.DeleteAsync("http://localhost:57135/api/Employees/3").Result;
Console.WriteLine("{0}\t{1}", "StatusCode:", response.StatusCode);
Console.ReadKey();
}
}
}

Result

Reflection in SQL Table

I hope you enjoyed this article. Your valuable feedback, question, or comments about this article are always welcomed.