Create Web API in MVC 6

• Add Using statement for Microsoft.Framework.DependencyInjection.
• Add the following method to the Startup class.

using System;  
using Microsoft.AspNet.Builder;  
using Microsoft.AspNet.Http;  
using Microsoft.Framework.DependencyInjection; // add new  

namespace WebApplication1  
{  
    public class Startup  
    {  
        public void Configure(IApplicationBuilder app)  
        {  
            // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940  
            app.UseWelcomePage();  
            app.UseMvc();  
        }  

        public void ConfigureServices(IServiceCollection services)  
        {  
            services.AddMvc();  
        }  
    }  
}  

Add a Model

using System;  
using System.ComponentModel.DataAnnotations;  

namespace WebApplication1.Model  
{  
    public class Customer  
    {  
        public int CustomerId { get; set; }  
        
        [Required]  
        public string Name { get; set; }  
    }  
}  

Add Controller

using Microsoft.AspNet.Mvc;  
using System.Collections.Generic;  
using System.Linq;  
using WebApplication1.Model;  

// For more information on enabling MVC for empty projects, visit http://go.microsoft.com/fwlink/?LinkID=397860  

namespace WebApplication1.Controllers  
{  
    //[Route("api/[controller]")]  
    public class HomeController : Controller  
    {  
        // GET: /<controller>/  
        static readonly new List<Customer> _items = new List<Customer>()  
        {  
            new Customer { CustomerId = 1, Name = "Atul Rawat" },  
            new Customer { CustomerId = 2, Name = "Shridhar" },  
        };  

        public IEnumerable<Customer> Get()  
        {  
            return _items;  
            // return new string[] {""}  
        }  

        //[HttpGet("{id:int}", Name = "GetByIdRoute")]  
        public IActionResult GetById(int id)  
        {  
            var its = _items.FirstOrDefault(x => x.CustomerId == id);  
            if (its == null)  
            {  
                return HttpNotFound();  
            }  
            return new ObjectResult(its);  
        }  

        public void CreateCustomer([FromBody] Customer item)  
        {  
            if (!ModelState.IsValid)  
            {  
                Context.Response.StatusCode = 400;  
            }  
            else  
            {  
                item.CustomerId = 1 + _items.Max(x => (int?)x.CustomerId) ?? 0;  
                _items.Add(item);  

                string url = Url.RouteUrl("GetByIdRoute", new { id = item.CustomerId },  
                    Request.Scheme, Request.Host.ToUriComponent());  

                Context.Response.StatusCode = 201;  
                Context.Response.Headers["Location"] = url;  
            }  
        }  

        // [HttpDelete("{id}")]  
        public IActionResult DeleteItem(int id)  
        {  
            var item = _items.FirstOrDefault(x => x.CustomerId == id);  
            if (item == null)  
            {  
                return HttpNotFound();  
            }  
            _items.Remove(item);  
            return new HttpStatusCodeResult(204);   
        }  
    }  
}  

Explanation of the preceding code

In this part, I will describe the Homecontroller class.

Routing

The routing attribute defines a URL template of the controller.

[Route("api/[controller]")]

HTTP Methods

The [HttpGet], [HttpPost] and [HttpDelete] attributes define the HTTP methods for the controller actions.

public IEnumerable<Customer> Get() {} // [HttpGet]  
public IActionResult GetById(int id) {} // [HttpGetById]  
public void CreateCustomer([FromBody] Customer item) {} // [HttpPost]  
public IActionResult DeleteItem(int id) {} // [HttpDelete]  

The {customerid:int} int constrains the variable to match an integer so the URLs will match.

http://localhost/api/home/1
http://localhost/api/home/42

Summary

In this article, we have created a Web API in MVC 6 using a model, controller, and HTTP methods.