A Complete Guide - ASP.NET Web API Setting Up Development Environment in Visual Studio

Step-by-Step Guide

Step 1: Install Visual Studio

Step 3: Explore the Generated Project

Upon creation, the project will contain several default files and folders:

• Controllers: Contains the API controllers.
• Program.cs: Entry point for the application.
• appsettings.json: Configuration file.

Step 4: Add a Simple Controller

If you unchecked Use controllers (uncheck to use minimal APIs) during project configuration, you can add a controller manually.

1. Add a Controller Class:

   • In Solution Explorer, right-click on the Controllers folder, then select Add > Controller.
   • Choose API Controller with read/write actions.
   • Name your controller ItemsController (make sure the filename ends with Controller.cs).
   • Click Add.

2. Modify the Controller:

   • A class named ItemsController will be generated with some sample actions. Let's modify it slightly.

   using Microsoft.AspNetCore.Mvc; namespace MyFirstWebApi.Controllers { [ApiController] [Route("[controller]")] public class ItemsController : ControllerBase { private static readonly List<string> _items = new List<string>{"Item1", "Item2"}; [HttpGet] public ActionResult<IEnumerable<string>> Get() { return _items; } [HttpGet("{id}")] public ActionResult<string> Get(int id) { if (id >= _items.Count || id < 0) { return NotFound(); } return _items[id]; } [HttpPost] public IActionResult Post([FromBody] string item) { _items.Add(item); return CreatedAtAction(nameof(Get), new { id = _items.Count - 1 }, item); } [HttpPut("{id}")] public IActionResult Put(int id, [FromBody] string item) { if (id >= _items.Count || id < 0) { return NotFound(); } _items[id] = item; return NoContent(); } [HttpDelete("{id}")] public IActionResult Delete(int id) { if (id >= _items.Count || id < 0) { return NotFound(); } _items.RemoveAt(id); return NoContent(); } }
   }
   

Step 5: Use Minimal APIs Instead

Minimal APIs allow you to create an API with less boilerplate code. Follow these steps to configure the project with minimal APIs:

1. Open Program.cs.

2. Modify the file to define a minimal API:

   var builder = WebApplication.CreateBuilder(args); // Add services to the container.
   // builder.Services.AddControllers(); var app = builder.Build(); // Configure the HTTP request pipeline.
   if (app.Environment.IsDevelopment()) { app.UseDeveloperExceptionPage();
   } app.UseHttpsRedirection(); // Sample in-memory items list
   var items = new List<string>{"Item1", "Item2"}; // Define endpoints
   app.MapGet("/items", () => items);
   app.MapGet("/items/{id}", (int id) => id >= items.Count || id < 0 ? Results.NotFound() : Results.Ok(items[id]));
   app.MapPost("/items", ([FromBody] string item) => { items.Add(item); return Results.Created($"/items/{items.Count - 1}", item);
   });
   app.MapPut("/items/{id}", (int id, [FromBody] string item) => { if (id >= items.Count || id < 0) { return Results.NotFound(); } items[id] = item; return Results.NoContent();
   });
   app.MapDelete("/items/{id}", (int id) => { if (id >= items.Count || id < 0) { return Results.NotFound(); } items.RemoveAt(id); return Results.NoContent();
   }); app.Run();
   

Step 6: Run the Project

1. Run the Application:
   • Press F5 or click the green play button in Visual Studio to run your web application.
2. View the Swagger UI (if not using minimal APIs):
   • If you used the default project template with controllers enabled, Visual Studio should automatically launch the Swagger UI for testing your API.
3. Test Minimal APIs Endpoints:
   • You can test the endpoints manually using a browser or tools like Postman or curl.

Step 7: Test Your API Endpoints

You can use different tools to test your API endpoints.