Create Web API Hello World First application

In this article I am going to explain how to create Web API first Hello world application.

In previous article I have explained Introduction to Web API.

I am using Visual studio 2019 and .net framework to create this application.

Implementation:

STEP 1 : Open VS 2019. Click on create a new project and select ASP.Net web application (.Net Framework).

STEP 2 : Configure new project window will be open. Enter the project Name, select location and click on Create button.

STEP 3 : Create a new ASP.NET Web application window will be open. Select Empty and check the Web API from add folders & core reference. If you want to create MVC + Web API, then select the MVC option. 

Application will be created and looks as below attached screenshot.

Firstly, you need to check the important files of Web API application WebApiConfig.cs and Global.asax

WebApiConfig.cs

This file is very important because it configure the routes of incoming request. This file is located under App_Start folder and looks as shown below:

public static class WebApiConfig

    {

        public static void Register(HttpConfiguration config)

        {

            // Web API configuration and services

            // Web API routes

                 config.Routes.MapHttpRoute(

                name: "DefaultApi",

                routeTemplate: "api/{controller}/{id}",

                defaults: new { id = RouteParameter.Optional }

            );

        }

    }

Global.asax

This file has Application_Start method. This method is executed when application starts for first time. As you see Web API routes are configured in this method. If you check the definition of this, will redirect you to WebApiConfig.cs file.

protected void Application_Start()

        {

            GlobalConfiguration.Configure(WebApiConfig.Register);

        }

STEP 4 : Now let move to next step. Add controller to project. Right click on Controllers folder >> Add >> select Controller. Select Web API 2 Controller-Empty, click on add button and enter controller name.

STEP 5 : Create a method. I have created a method (HelloMethod) and return the first application text.

Complete code of Controller (HelloController.cs)

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Net.Http;

using System.Web.Http;

using WEBAPI.Models;

namespace WEBAPI.Controllers

{

    public class HelloController : ApiController

    {

        [HttpGet]

        public string HelloMethod()

        {

            return "Web API Hello World (First Application)";

        }

    }

}

All done, now run the application. Type the URL according to WebApiConfig.cs file like Api/controller/Action/id e.g. https://localhost:44373/api/hello