在 JSON 文件中查找 JArray/JObject 元素

Question

在 'products' 标题下，我试图在 'price' 的 JSON 文件中找到 'handle' 变量的第一个值'variants' 标题下的 元素等于 '1.4'。

我一直在努力通过 JObject/JArray 进行查询，并想知道是否有办法做到这一点。这是我从中查询的 JSON 文件：

"products":[{
 "id":124534,
 "handle": "Data1", 
 "variants":[
    {
       "barcode":null,
       "sku":"M11-168-EN-NFNE-0",
       "price":1.5
    },
    {
       "barcode":null,
       "sku":"M11-168-EN-NFNE-0",
       "price":1.5
    }]
},
{
 "id":548562,
 "handle": "Data2", 
 "variants":[
    {
       "barcode":null,
       "sku":"M11-168-EN-NFNE-0",
       "price":1.4,
    }]
}]

对此的任何帮助将不胜感激。

Answer 1

假设这些是您的模型类：

public class Product
{
    public int Id { get; set; }
    public string Handle { get; set; }
    public Variant[] Variants { get; set; }   
}

public class Variant
{
    public string Barcode { get; set; }
    public string SKU { get; set; }
    public double Price { get; set; }
}

那么 LINQ 查询将如下所示：

static string GetTheFirstProductWhereOneOfItsVariantHasAGivenPrice(IEnumerable<Product> products, double expectedPrice)
{
    var product = products
        .FirstOrDefault(p => p.Variants.Any(variant => Math.Abs(variant.Price - expectedPrice) < 0.05));
    return product?.Handle ?? "Not Found";
}

• 它试图找到第一个产品（如果有的话）products.FirstOrDefault
• 有一个给定价格的变体（在误差范围内）Variants.Any
• 如果有，则返回其Handle 属性，否则返回Not Found

用法如下所示：

static void Main(string[] args)
{

    const double expectedPrice = 1.4;
    string secondProductWithTheGivenPrice =
        "[{\r\n \"id\":124534,\r\n \"handle\": \"Data1\", \r\n \"variants\":[\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.5\r\n    },\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.5\r\n    }]\r\n},\r\n{\r\n \"id\":548562,\r\n \"handle\": \"Data2\", \r\n \"variants\":[\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.4,\r\n    }]\r\n}]";

    var products = JsonConvert.DeserializeObject<Product[]>(secondProductWithTheGivenPrice);
    Console.WriteLine(GetTheFirstProductWhereOneOfItsVariantHasAGivenPrice(products, expectedPrice));

    string firstProductWithTheGivenPrice =
        "[{\r\n \"id\":124534,\r\n \"handle\": \"Data1\", \r\n \"variants\":[\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.5\r\n    },\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.4\r\n    }]\r\n},\r\n{\r\n \"id\":548562,\r\n \"handle\": \"Data2\", \r\n \"variants\":[\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.4,\r\n    }]\r\n}]";

    products = JsonConvert.DeserializeObject<Product[]>(firstProductWithTheGivenPrice);
    Console.WriteLine(GetTheFirstProductWhereOneOfItsVariantHasAGivenPrice(products, expectedPrice));

    string withoutGivenPrice =
        "[{\r\n \"id\":124534,\r\n \"handle\": \"Data1\", \r\n \"variants\":[\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.5\r\n    },\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.6\r\n    }]\r\n},\r\n{\r\n \"id\":548562,\r\n \"handle\": \"Data2\", \r\n \"variants\":[\r\n    {\r\n       \"barcode\":null,\r\n       \"sku\":\"M11-168-EN-NFNE-0\",\r\n       \"price\":1.3,\r\n    }]\r\n}]";

    products = JsonConvert.DeserializeObject<Product[]>(withoutGivenPrice);
    Console.WriteLine(GetTheFirstProductWhereOneOfItsVariantHasAGivenPrice(products, expectedPrice));

}

输出如下所示：

Data2
Data1
Not Found