Change Name of 'Key' and 'Value' when using JSON.NET to serialize complex Dictionary

Question

I am running into a strange problem with serializing data with json.net. Mainly, I am trying to rename the 'Key' and 'Value' names in the outgoing json to be something more descriptive. Specifically, I want the IRequest related 'Key' to be called 'Request' and the IQuoteTimeSeries 'Value' to be 'DataSeries'

Note, this will not be deserialized. It is only used in data analysis on the web page.

The data repository object I am serializing is a Dictionary<IRequest, IQuoteTimeSeries> object. The IRequest represents a specific request for data and the IQuoteTimeSeries is the object that contains the returning data as a SortedDictionary<DateTime, IQuote>. This is a series of data sorted by timestamp. In this example, I only have one item in the TimeSeries for brevity, but in most cases there would be many items.

Everything needs to be organized together, serialized and sent out to be consumed by JavaScript.

Here is the basic code for these objects;

[JsonArray]
public class QuoteRepository : Dictionary<IRequest, IQuoteTimeSeries>, IQuoteRepository
{
    public QuoteRepository() { }   

    public void AddRequest(IRequest request)
    {
        if (!this.ContainsKey(request))
        {
            IQuoteTimeSeries tSeries = new QuoteTimeSeries(request);
            this.Add(request, tSeries);
        }
    }

    public void AddQuote(IRequest request, IQuote quote)
    {        
        if (!this.ContainsKey(request))
        {
            QuoteTimeSeries tSeries = new QuoteTimeSeries(request);
            this.Add(request, tSeries);
        }        
        this[request].AddQuote(quote);        
    }    

    IEnumerator<IQuoteTimeSeries>  Enumerable<IQuoteTimeSeries>.GetEnumerator()
    {
        return this.Values.GetEnumerator();
    }
}

A quote time series looks like this;

[JsonArray]
public class QuoteTimeSeries: SortedDictionary<DateTime, IQuote>, IQuoteTimeSeries
{  
    public QuoteTimeSeries(IRequest request)
    {
        Request = request;
    }
    public IRequest Request { get; }
    public void AddQuote(IQuote quote)
    {
        this[quote.QuoteTimeStamp] = quote;
    }

    public void MergeQuotes(IQuoteTimeSeries quotes)
    {
        foreach (IQuote item in quotes)
        {
            this[item.QuoteTimeStamp] = item;
        }
    }

    IEnumerator<IQuote> IEnumerable<IQuote>.GetEnumerator()
    {
        return this.Values.GetEnumerator();
    }

}

The code used to serialize this is fairly simple:

IQuoteRepository quotes = await requests.GetDataAsync();

JsonSerializerSettings settings = new JsonSerializerSettings
{
    ContractResolver = QuoteRepositoryContractResolver.Instance,
    NullValueHandling = NullValueHandling.Ignore
};

return Json<IQuoteRepository>(quotes, settings);

I added a contract resolver with the intention of overriding the property writing. The property.PropertyName = code is being hit and the property names are being changed, but the output JSON is unaffected.

public class QuoteRepositoryContractResolver : DefaultContractResolver
{
    public static readonly QuoteRepositoryContractResolver Instance = new QuoteRepositoryContractResolver();

    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
    {
        JsonProperty property = base.CreateProperty(member, memberSerialization);

        if (property.DeclaringType == typeof(KeyValuePair<IRequest, IQuoteTimeSeries>))
        {
            if (property.PropertyName.Equals("Key", StringComparison.OrdinalIgnoreCase))
            {
                property.PropertyName = "Request";
            }
            else if (property.PropertyName.Equals("Value", StringComparison.OrdinalIgnoreCase))
            {
                property.PropertyName = "Data";
            }
        }
        else if (property.DeclaringType == typeof(KeyValuePair<DateTime, IQuote>))
        {
            if (property.PropertyName.Equals("Key", StringComparison.OrdinalIgnoreCase))
            {
                property.PropertyName = "TimeStamp";
            }
            else if (property.PropertyName.Equals("Value", StringComparison.OrdinalIgnoreCase))
            {
                property.PropertyName = "Quote";
            }
        }
        return property;
    }
}

The output JSON is odd. The Key and Value items are completely unchanged, even though I did change their names in the code.

[
    {
        "Key": {
            "QuoteDate": "2016-05-12T00:00:00-04:00",
            "QuoteType": "Index",
            "Symbol": "SPY",
            "UseCache": true
        },
        "Value": [
            {
                "Key": "2016-05-11T16:00:01-04:00",
                "Value": {
                    "Description": "SPDR S&amp;P 500",
                    "High": 208.54,
                    "Low": 206.50,
                    "Change": -1.95,
                    "ChangePer": -0.94,
                    "Price": 206.50,
                    "QuoteTimeStamp": "2016-05-11T16:00:01-04:00",
                    "Symbol": "SPY"
                }
            }
        ]
    },
    {
        "Key": {
            "QuoteDate": "2016-05-12T00:00:00-04:00",
            "QuoteType": "Stock",
            "Symbol": "GOOG",
            "UseCache": true
        },
        "Value": [
            {
                "Key": "2016-05-11T16:00:00-04:00",
                "Value": {
                    "Description": "Alphabet Inc.",
                    "High": 724.48,
                    "Low": 712.80,
                    "Change": -7.89,
                    "ChangePer": -1.09,
                    "Price": 715.29,
                    "QuoteTimeStamp": "2016-05-11T16:00:00-04:00",
                    "Symbol": "GOOG"
                }
            }
        ]
    }
]

Does anyone know how to change the 'Key' and 'Value' items properly?

@Brian Rogers Thank you for the cleanup. My typing skills aren't always that great at 4:00 AM in the morning. :-) — drobertson
– drobertson, Commented May 12, 2016 at 16:27

Brian Rogers · Accepted Answer · 2016-05-12 15:57:13Z

5

One way to solve this is to use a custom JsonConverter for your dictionary-based classes. The code is actually pretty straightforward.

public class CustomDictionaryConverter<K, V> : JsonConverter
{
    private string KeyPropertyName { get; set; }
    private string ValuePropertyName { get; set; }

    public CustomDictionaryConverter(string keyPropertyName, string valuePropertyName)
    {
        KeyPropertyName = keyPropertyName;
        ValuePropertyName = valuePropertyName;
    }

    public override bool CanConvert(Type objectType)
    {
        return typeof(IDictionary<K, V>).IsAssignableFrom(objectType);
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        IDictionary<K, V> dict = (IDictionary<K, V>)value;
        JArray array = new JArray();
        foreach (var kvp in dict)
        {
            JObject obj = new JObject();
            obj.Add(KeyPropertyName, JToken.FromObject(kvp.Key, serializer));
            obj.Add(ValuePropertyName, JToken.FromObject(kvp.Value, serializer));
            array.Add(obj);
        }
        array.WriteTo(writer);
    }

    public override bool CanRead
    {
        get { return false; }
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }
}

When it is time to serialize, add the converters to the JsonSerializerSettings like this:

JsonSerializerSettings settings = new JsonSerializerSettings
{
    Converters = new List<JsonConverter>
    {
        new CustomDictionaryConverter<IRequest, IQuoteTimeSeries>("Request", "Data"),
        new CustomDictionaryConverter<DateTime, IQuote>("TimeStamp", "Quote")
    },
    Formatting = Formatting.Indented
};

string json = JsonConvert.SerializeObject(repo, settings);

Fiddle: https://dotnetfiddle.net/roHEtx

answered May 12, 2016 at 15:57

Brian Rogers

130k31 gold badges315 silver badges315 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

drobertson Over a year ago

Thanks. I ran some tests and the code above worked exactly like I needed it to. I have been beating my head against a wall trying to figure out how to modify those values. Your answer was perfect.

Brian Rogers Over a year ago

Glad I could help.

StingyJack · Accepted Answer · 2016-05-12 16:43:42Z

-1

Converting your dictionary from Dictionary<IRequest, IQuoteTimeSeries> to List<KeyValuePair<IRequest, IQuoteTimeSeries>> should also work.

answered May 12, 2016 at 16:43

StingyJack

19.6k11 gold badges69 silver badges126 bronze badges

Collectives™ on Stack Overflow

Change Name of 'Key' and 'Value' when using JSON.NET to serialize complex Dictionary

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related