oap_labs/Model/JSONDataProvider.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Serialization.Json;
using System.Text;
using System.Threading.Tasks;

namespace wpf_template.Model
{
    public class JSONDataProvider : IDataProvider
    {
        private List<Product> products;
        public JSONDataProvider() 
        {
            var serializer = new DataContractJsonSerializer(typeof(Product[]));
            using(var sr = new StreamReader("./products.json"))
            {
                products = ((Product[])serializer.ReadObject(sr.BaseStream)).ToList();
            }
        }
        public IEnumerable<Product> GetProducts()
        {
            return products;
        }

        public IEnumerable<ProductCategory> GetCategories()
        {
            return new ProductCategory[]
            {
                new ProductCategory {title = "Смартфон"},
                new ProductCategory {title = "Ноутбук"},
                new ProductCategory {title = "Смарт-Часы"},
                new ProductCategory {title = "Монитор"}
            };
        }

        public IEnumerable<ProductPrice> GetPrices()
        {
            return new ProductPrice[]
            {
                new ProductPrice{title="Все цены", priceFrom = 0, priceTo = 999999},
                new ProductPrice{title="До 10.000", priceFrom = 0, priceTo = 10000},
                new ProductPrice{title="От 10.000 до 20.000", priceFrom = 10000, priceTo = 20000},
                new ProductPrice{title="От 20.000 до 50.000", priceFrom = 20000, priceTo = 50000},
                new ProductPrice{title="Дороже 50.000", priceFrom = 50000, priceTo = 999999 }
            };
        }
        public IEnumerable<ProductCompany> GetCompanies()
        {
            return new ProductCompany[]
            {
                new ProductCompany{title = "Apple"},
                new ProductCompany{title = "Xiaomi"},
                new ProductCompany{title = "Huawei"},
                new ProductCompany{title = "POCO"},
                new ProductCompany{title = "Asus"},
                new ProductCompany{title = "Lenovo"},
                new ProductCompany{title = "Samsung"},
                new ProductCompany{title = "Acer"},
                new ProductCompany{title = "AOC"}
            };
        }
    }
}