c# - 将 JSON 反序列化为 List 时出错

Question

我想将此 json 反序列化为 Product 对象列表，但出现此错误:

Newtonsoft.Json.JsonSerializationException: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[ShoppingList.Product]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly. To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.

这是我的代码:

{
    "records": [
        {
            "id": "60",
            "name": "Rolex Watch",
            "description": "Luxury watch.",
            "price": "25000",
            "category_id": "1",
            "category_name": "Fashion"
        },
        {
            "id": "48",
            "name": "Bristol Shoes",
            "description": "Awesome shoes.",
            "price": "999",
            "category_id": "5",
            "category_name": "Movies"
        },
        {
            "id": "42",
            "name": "Nike Shoes for Men",
            "description": "Nike Shoes",
            "price": "12999",
            "category_id": "3",
            "category_name": "Motors"
        }
    ]   
}

public class Product
{
    public int id { get; set; }
    public string name { get; set; }
    public string description { get; set; }
    public decimal price { get; set; }
    public int category_id { get; set; }
    public string category_name { get; set; }
}

public async Task<List<Product>> GetProductsAsync()
    {
        Products = new List<Product>();

        var uri = new Uri("https://hostname/api/product/read.php");

        try
        {
            var response = await client.GetAsync(uri);
            if (response.IsSuccessStatusCode)
            {
                var content = await response.Content.ReadAsStringAsync();
                Products = JsonConvert.DeserializeObject<List<Product>>(content);
            }
        }
        catch (Exception )
        {
            throw;
        }

        return Products;
    }

Answer 1

你的 Json 不是 List<Product> ，它是一个具有名为 records 的单个属性的对象是 List<Product> .

所以您的实际 C# 模型是这样的:

public class RootObject
{
    public List<Product> records { get; set; }
}

然后你像这样反序列化:

RootObject productsRoot = JsonConvert.DeserializeObject<RootObject>(content);