从TD Ameritrade反序列化JSON

Question

我从TD Ameritrade的API中拉入报价数据，并生成以下JSON：

{
  "AAPL": {
    "52WkHigh": 145.09,
    "52WkLow": 53.1525,
    "askId": "P",
    "askPrice": 121.08,
    "askSize": 1700,
    "assetMainType": "EQUITY",
    "assetType": "EQUITY",
    "bidId": "P",
    "bidPrice": 121.06,
    "bidSize": 600,
    "bidTick": " ",
    "closePrice": 121.03,
    "cusip": "037833100",
    "delayed": "false",
    "description": "Apple Inc. - Common Stock",
    "digits": 4,
    "divAmount": 0.82,
    "divDate": "2021-02-05 00:00:00.000",
    "divYield": 0.68,
    "exchange": "q",
    "exchangeName": "NASD",
    "highPrice": 121.17,
    "lastId": "D",
    "lastPrice": 121.08,
    "lastSize": 200,
    "lowPrice": 119.16,
    "marginable": "true",
    "mark": 121.03,
    "markChangeInDouble": 0.0,
    "markPercentChangeInDouble": 0.0,
    "nAV": 0.0,
    "netChange": 0.05,
    "netPercentChangeInDouble": 0.0413,
    "openPrice": 120.4,
    "peRatio": 32.9702,
    "quoteTimeInLong": 1615597198023,
    "regularMarketLastPrice": 121.03,
    "regularMarketLastSize": 7,
    "regularMarketNetChange": 0.0,
    "regularMarketPercentChangeInDouble": 0.0,
    "regularMarketTradeTimeInLong": 1615582801729,
    "securityStatus": "Normal",
    "shortable": "true",
    "symbol": "AAPL",
    "totalVolume": 88105050,
    "tradeTimeInLong": 1615597198932,
    "volatility": 0.0085
  }
}

从JSON创建的类：

public class Quote
{
    public float _52WkHigh { get; set; }
    public float _52WkLow { get; set; }
    public string askId { get; set; }
    public float askPrice { get; set; }
    public int askSize { get; set; }
    public string assetMainType { get; set; }
    public string assetType { get; set; }
    public string bidId { get; set; }
    public float bidPrice { get; set; }
    public int bidSize { get; set; }
    public string bidTick { get; set; }
    public float closePrice { get; set; }
    public string cusip { get; set; }
    public string delayed { get; set; }
    public string description { get; set; }
    public int digits { get; set; }
    public float divAmount { get; set; }
    public string divDate { get; set; }
    public float divYield { get; set; }
    public string exchange { get; set; }
    public string exchangeName { get; set; }
    public float highPrice { get; set; }
    public string lastId { get; set; }
    public float lastPrice { get; set; }
    public int lastSize { get; set; }
    public float lowPrice { get; set; }
    public string marginable { get; set; }
    public float mark { get; set; }
    public float markChangeInDouble { get; set; }
    public float markPercentChangeInDouble { get; set; }
    public float nAV { get; set; }
    public float netChange { get; set; }
    public float netPercentChangeInDouble { get; set; }
    public float openPrice { get; set; }
    public float peRatio { get; set; }
    public long quoteTimeInLong { get; set; }
    public float regularMarketLastPrice { get; set; }
    public int regularMarketLastSize { get; set; }
    public float regularMarketNetChange { get; set; }
    public float regularMarketPercentChangeInDouble { get; set; }
    public long regularMarketTradeTimeInLong { get; set; }
    public string securityStatus { get; set; }
    public string shortable { get; set; }
    public string symbol { get; set; }
    public int totalVolume { get; set; }
    public long tradeTimeInLong { get; set; }
    public float volatility { get; set; }
}

我调用Python脚本来获取JSON数据，然后将其重定向到我的C#应用程序。但是，当我反序列化它时，没有数据填充：

    public void GetQuotes(string symbol)
    {
        var errors = "";
        var results = "";
        this.psi.Arguments = $"\"{this.script}\" -q {symbol}";
        Quote quote;

        using (var process = Process.Start(psi))
        {
            errors = process.StandardError.ReadToEnd();
            results = process.StandardOutput.ReadToEnd();
            Debug.Print(results);
            
            quote = JsonConvert.DeserializeObject<Quote>(results);
            
        }

        MessageBox.Show(quote.symbol);
    }

我已经能够相对一致地成功地反序列化JSON，但是我不明白为什么要从这个Json加载空白对象。

Answer 1

您需要创建一个包含Quote对象的根对象。

public class RootObject 
{
  public Quote AAPL { get;set;}
}

并反序列化到这个，

var rootObject = JsonConvert.DeserializeObject<RootObject>(results);
Quote quote = rootObject.AAPL;

当您反序列化到Quote时，您将得到空值，因为原始json中没有与任何Quote属性匹配的属性。由于您的JSON包含1个属性(AAPL)，并且它的值是Quote类型，因此您必须反序列化为RootObject。

根据您对变量键的观点，您应该反序列化到Dictionary<string, Quote>。

var obj = JsonConvert.DeserializeObject<Dictionary<string, Quote>>(results);
Quote quote = obj.FirstOrDefault().Value;

您还可以列出所有键并使用foreach循环，但是如果您知道总是只有一个键，FirstOrDefault()也可以工作。

Answer 2

感谢Jawad的快速提示。因为'AAPL‘是一个不断变化的键，所以我不得不将JSON反序列化为一个Dictionary<string, Quote>来填充数据：

    public void GetQuotes(string symbol)
    {
        var errors = "";
        var results = "";
        this.psi.Arguments = $"\"{this.script}\" -q {symbol}";
        Dictionary<string, Quote> quotes;

        using (var process = Process.Start(psi))
        {
            errors = process.StandardError.ReadToEnd();
            results = process.StandardOutput.ReadToEnd();
            Debug.Print(results);

            
            quotes = JsonConvert.DeserializeObject<Dictionary<string, Quote>>(results);
        }
    }