JSON反序列化物件回傳null

源代碼 - 主類

        string responseBody = await response.Content.ReadAsStringAsync();

        status.result deserializeObject = JsonConvert.DeserializeObject<status.result>(responseBody);

        Debug.WriteLine(deserializeObject.SafeGasPrice.ToString());

源代碼 - JSON 類

    public class status
    {
        public class result
        {
            [JsonProperty(PropertyName = "SafeGasPrice")]
            public int SafeGasPrice { get; set; }

            [JsonProperty(PropertyName = "ProposeGasPrice")]
            public int ProposeGasPrice { get; set; }

            [JsonProperty(PropertyName = "FastGasPrice")]
            public int FastGasPrice { get; set; }
        }
    }

輸出

{"status":"1","message":"OK","result":{"LastBlock":"14296250","SafeGasPrice":"96","ProposeGasPrice":"96","FastGasPrice":"97","suggestBaseFee":"95.407119606","gasUsedRatio":"0.174721033333333,0.523179548504219,0.056945596868572,0.999939743363228,0.953861217484817"}}

0

問題

我目前不明白為什么會輸出 null，我的猜測是我錯誤地實作了 json 反序列化類。

uj5u.com熱心網友回復：

您的資料模型與提供的 JSON 不對應，它缺少與外部{"result": { }}物件對應的型別：

{
   "status":"1",
   "message":"OK",
   "result":{
      // This inner object corresponds to your model.
      "LastBlock":"14296250",
      "SafeGasPrice":"96",
      "ProposeGasPrice":"96",
      "FastGasPrice":"97",
      "suggestBaseFee":"95.407119606",
      "gasUsedRatio":"0.174721033333333,0.523179548504219,0.056945596868572,0.999939743363228,0.953861217484817"
   }
}

要解決這個問題，您需要引入一個外部包裝模型。你可以像這樣做一個明確的：

public class Root
{
    public string status { get; set; }
    public string message { get; set; }
    public Result result { get; set; }
}

public class Result
{
    [JsonProperty(PropertyName = "SafeGasPrice")]
    public int SafeGasPrice { get; set; }

    [JsonProperty(PropertyName = "ProposeGasPrice")]
    public int ProposeGasPrice { get; set; }

    [JsonProperty(PropertyName = "FastGasPrice")]
    public int FastGasPrice { get; set; }
}

像這樣反序列化：

var deserializeObject = JsonConvert.DeserializeObject<Root>(responseBody)?.result;

或者，您可以對根模型使用匿名型別，如下所示：

var deserializeObject = JsonConvert.DeserializeAnonymousType(responseBody, new { result = default(Result) })?.result;

無論哪種方式，您現在都可以成功反序列化內部嵌套屬性。

那么你做錯了什么？在您的問題中，您宣告result為嵌套型別：

public class status
{
    public class result
    {
        [JsonProperty(PropertyName = "SafeGasPrice")]
        public int SafeGasPrice { get; set; }

        [JsonProperty(PropertyName = "ProposeGasPrice")]
        public int ProposeGasPrice { get; set; }

        [JsonProperty(PropertyName = "FastGasPrice")]
        public int FastGasPrice { get; set; }
    }
}

All this does is define a type result within the scope of another type status. It does not create a property named result within status. As there is no need for such nesting I recommend moving result out from inside status and renaming it Result to follow standard .NET naming conventions.

Demo fiddle here.

標籤：C＃ json uwp json.net uwp-xml

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