c# Deserialize unlabelled JSON array

问题

I am attempting to deserialize a piece of JSON with a specific structure like so:

{  
    "label1": "value1",  
    "label2": [  
        [  
            [  
                "concept_id_1",  
                "concept_1"  
            ],  
            score_1  
        ],  
        [  
            [  
                "concept_id_2",  
                "concept_2"  
            ],  
            score_2  
        ],  
        ……  
    ],  
    "label3": "value3",  
    "label4": "value4"  
}  

For what it's worth, the scores are floats and everything else is a string. The number of returned concepts under "label2" is variable.

I'm attempting to deserialize it using JSON.net. The only content I actually care about is the inside nest of arrays labelled "label2", however the lack of labels inside the arrays is blocking me at every turn.

I've tried a variety of approaches, but the most successful so far seems to be this:

public class Parsed_JSON {
    public string label1 { get; set; }
    public ICollection<Full_Result> label2 { get; set; }
    public string label3 { get; set; }
    public string label4 { get; set; }
}

public class Full_Result {
    public IList<string> values { get; set; }
    public float score { get; set; }
}

Parsed_JSON result = JsonConvert.DeserializeObject<Parsed_JSON>(JSON);

However this is failing with the error:

Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'JSON_Parsing+Full_Result' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.

Ultimately I'll be looking to iterate through the contents of label2 so that I can build a DataTable of them like so:

concept_id_1   concept_1   score_1  
concept_id_2   concept_2   score_2

How can I deserialize this JSON?

回答1:

You can use the custom JsonConverter ObjectToArrayConverter<Full_Result> from this answer to C# JSON.NET - Deserialize response that uses an unusual data structure to deserialize your JSON into your existing typed data model. Modify Full_Result as follows:

[JsonConverter(typeof(ObjectToArrayConverter<Full_Result>))]
public class Full_Result 
{
    [JsonProperty(Order = 1)]
    public IList<string> values { get; set; }
    [JsonProperty(Order = 2)]
    public float score { get; set; }
}

And you will now be able to deserialize as follows:

Parsed_JSON result = JsonConvert.DeserializeObject<Parsed_JSON>(JSON);

Notes:

• ObjectToArrayConverter<T> works by mapping the serializable members of T to an array, where the array sequence is defined by the value of the JsonPropertyAttribute.Order attribute applied to each member. Data contract attributes with DataMemberAttribute.Order set could be used instead, if you prefer.

• In your JSON the "score" values are not actually numbers:

  score_1
  score_2
  

  I am assuming that this is a typo in the question and that these values are in fact well-formed numbers as defined by the JSON standard.

Sample fiddle here.

来源：https://stackoverflow.com/questions/52743860/c-sharp-deserialize-unlabelled-json-array