如何將這個 JSON 反序列化為一個列表？

Question

我在將 JSON 文件從 web 反序列化為列表時遇到問題。 每次我執行代碼時，它都會拋出 Newtonsoft.Json.JsonSerializationException。

我的代碼在下面，但它不執行並顯示 Newtonsoft.Json.JsonSerializationException。

static void Main(string[] args)
        {
            List<Root> coinDatas = new List<Root>(); ;

            callApi(coinDatas);
            Console.ReadKey();
        }

        private static async void callApi(List<Root> coinDatas)
        {
            string url = "https://api.coinstats.app/public/v1/coins?skip=0&limit=50&currency=USD";

            HttpClient httpClient = new HttpClient();

            var httpResponse = await httpClient.GetAsync(url);
            string jsonResponse = await httpResponse.Content.ReadAsStringAsync();

            coinDatas = JsonConvert.DeserializeObject<List<Root>>(jsonResponse);
        }

public class Coin
    {
        public string id { get; set; }
        public string icon { get; set; }
        public string name { get; set; }
        public string symbol { get; set; }
        public int rank { get; set; }
        public double price { get; set; }
        public double priceBtc { get; set; }
        public double volume { get; set; }
        public double marketCap { get; set; }
        public double availableSupply { get; set; }
        public double totalSupply { get; set; }
        public double priceChange1h { get; set; }
        public double priceChange1d { get; set; }
        public double priceChange1w { get; set; }
        public string contractAddress { get; set; }
        public int? decimals { get; set; }
    }

    public class Root
    {
        public List<Coin> coins { get; set; }
    }

Answer 1

我從你的 url 下載了 JSON。它看起來像這樣：

{
    "coins": [
        {
            "id": "bitcoin",
            "icon": "https://static.coinstats.app/coins/1650455588819.png",
            "name": "Bitcoin",
            "symbol": "BTC",
            "rank": 1,
            "price": 16591.950104477022,
            "priceBtc": 1,
            "volume": 9476109498.476653,
            "marketCap": 319384453847.01608,
            "availableSupply": 19249362,
            "totalSupply": 21000000,
            "priceChange1h": 0.15,
            "priceChange1d": 0.05,
            "priceChange1w": -1.21,
            "websiteUrl": "http://www.bitcoin.org",
            "twitterUrl": "https://twitter.com/bitcoin",
            "exp": [
                "https://blockchair.com/bitcoin/",
                "https://btc.com/",
                "https://btc.tokenview.io/"
            ]
        }
    ]
}

我想 coinDatas coinDatas = JsonConvert.DeserializeObject<List<Root>>(jsonResponse);中的 ytour 問題線。

你只有一個根元素，點亮了它們的列表。

而且，順便說一下，您的代碼不會返回任何值。

我建議你將你的方法改寫成這樣：

private static async Task<Root> callApiAsync()
{
    string url = "https://api.coinstats.app/public/v1/coins?skip=0&limit=50&currency=USD";

    HttpClient httpClient = new HttpClient();

    var httpResponse = await httpClient.GetAsync(url);
    string jsonResponse = await httpResponse.Content.ReadAsStringAsync();

    return JsonConvert.DeserializeObject<Root>(jsonResponse);
}

然后您可以在 Main 中使用此方法（也請注意此方法中的async詞）：

static async void Main(string[] args)
{
    var coinDatas = await callApiAsync();
    Console.ReadKey();
}

Answer 2

如果你只需要一個硬幣列表，你可以將代碼更改為

async Task Main()
{

    List<Coin> coins = await callApiAsync();
    Console.ReadLine();
}

static async Task<List<Coin>> callApiAsync()
{
    string url = "https://api.coinstats.app/public/v1/coins?skip=0&limit=50&currency=USD";

    // your another code

    var data= JsonConvert.DeserializeObject<Root>(jsonResponse);
    return data.coins;
}