How to create Web API in ASP.NET C#

In this article, you will learn about ASP.Net Web API and how to create Web API in ASP.NET C# using Visual Studio. Keep reading on Top 30 ASP.Net Web API Interview Questions, Web API CRUD Operations using ASP.NET MVC and Entity Framework

What is Web API in ASP.NET

ASP.NET Web API is a framework for building HTTP based services that can be consumed from any client including browsers and mobile devices. ASP.NET Web API is an extension of WCF REST API.

ASP.NET Web API Characteristics

It is based on RESTful architecture.

Uses standard HTTP methods (GET, PUT, POST, DELETE).

It supports multiple text formats like XML, JSON, etc.

Completely stateless.

It supports ASP.NET MVC features.

Supports Self Hosting and IIS Hosting.

How to create Web API in ASP.NET C#

You can create a Web API project in two different ways.

Stand-alone Web API Project
Web API with MVC Project

In this article, I will explain how to create web API in asp.net c# without MVC step by step. Let’s get started with a new stand-alone web API project:-

Step 1: Open Visual Studio 2019 and click on Create a new project option.

This will open New Project popup as below:-

Step 2: Select the web template in the left panel and check the Web API checkbox and uncheck the Configure for Https from the right panel. Enter the name of the project, location and solution name as shown above. Clicking on OK will open a popup as shown below.

In the above popup, select Empty as a template and click ok. This will create an empty “WebAPIStart” project.

Now, let’s add Web API Controller by right-clicking on the Controllers folder -> select Controller.. this will open popup as below.

Select Controller in the left panel and Web API 2 Controller – Empty in the middle panel and click Add. This will open another popup to enter the name of your controller as below. Enter the controller name and click Add.

Now, we need to add action methods. Here, we will add some action methods as shown below.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using WebAPIStart.Models;

namespace WebAPIStart.Controllers
{
    public class UserController : ApiController
    {
        List<User> userList = new List<User>();
        public UserController()
        {
            userList.Add(new User { UserId = 1, Name = "Ravi", Address = "Noida" });
            userList.Add(new User { UserId = 2, Name = "Sachin", Address = "Agra" });
        }

        //api/user
        public IHttpActionResult GetUsers()
        {
            return Ok(userList);
        }

        //api/user/1
        public IHttpActionResult GetUser(int id)
        {
            User user = userList.Find(u => u.UserId == id);
            return Ok(user);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace WebAPIStart.Models
{
    public class User
    {
        public int UserId { get; set; }
        public string Name { get; set; }
        public string Address { get; set; }
    }
}

Now, compile and run the project and navigate to http://localhost:16053/api/user in the browser. It will display the following result.

Download Source Code

Conclusion

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