ASPNetCore/TestAppRuna/API/ProductController.cs

using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Threading.Tasks;
using TestAppRuna.Entities;

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

namespace TestAppRuna.API
{
    [Route("api/[controller]")]
    [ApiController]
    public class ProductController : ControllerBase
    {
        public ShopDbContext DB { get; }
        public ProductController(ShopDbContext shopDbContext)
        {
            this.DB = shopDbContext;
        }
        // GET: api/<ProductController>
        [HttpGet]
        public async Task<ActionResult<IEnumerable<ProductListItem>>> Get()
        {
            var data = await DB.Products
                .AsNoTracking()
                .Select(Q => new ProductListItem()
                {
                    ProductID = Q.ProductID,
                    Name = Q.Name,
                    Price = Q.Price
                })
                .OrderBy(Q => Q.Name)
                .ToListAsync();
            return data;
        }

        // GET api/<ProductController>/5
        [HttpGet("{id}")]
        public async Task<ActionResult<ProductListItem>> Get(Guid id)
        {
            var data = await DB.Products
                .AsNoTracking()
                .Where(Q => Q.ProductID == id)
                .Select(Q => new ProductListItem()
                {
                    ProductID = Q.ProductID,
                    Name = Q.Name,
                    Price = Q.Price,
                })
                .FirstOrDefaultAsync();

            if (data == null)
            {
                return NotFound();
            }
            return data;
        }

        // POST api/<ProductController>
        [HttpPost]
        public async Task<ActionResult<string>> Post([FromBody] ProductCreateUpdateModel model)
        {
            if(ModelState.IsValid == false)
            {
                return BadRequest();
            }
            Product product = new Product
            {
                ProductID = Guid.NewGuid(),
                Name = model.Name,
                Price = model.Price,
            };
            DB.Products.Add(product);
            await DB.SaveChangesAsync();
            return "OK";
        }

        // PUT api/<ProductController>/5
        [HttpPut("{id}")]
        public async Task<ActionResult<string>> Put(Guid id, [FromBody] ProductCreateUpdateModel model)
        {
            if(ModelState.IsValid == false)
            {
                return BadRequest();
            }
            var data = await DB.Products
                .Where(Q => Q.ProductID == id)
                .FirstOrDefaultAsync();
            if(data == null)
            {
                return NotFound();
            }
            data.Name = model.Name;
            data.Price = model.Price;
            await DB.SaveChangesAsync();
            return "OK";
        }

        // DELETE api/<ProductController>/5
        [HttpDelete("{id}")]
        public async Task<ActionResult<string>> Delete(Guid id)
        {
            var data = await DB.Products
                .Where(Q => Q.ProductID == id)
                .FirstOrDefaultAsync();
            if(data == null)
            {
                return NotFound();
            }
            DB.Products.Remove(data);
            await DB.SaveChangesAsync();
            return "OK";
        }
    }

    public class ProductListItem
    {
        public Guid ProductID { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
    }
    public class ProductCreateUpdateModel
    {
        [Required]
        [StringLength(255)]
        public string Name { get; set; }
        [Required]
        [Range(double.Epsilon,double.MaxValue)]
        public decimal Price { get; set; }
    }
}