Dante4 Dante4 - 1 month ago 22
C# Question

C# JSON.net Deserialization

Yesterday was first day when i met JSON and most of example that i find was where JSON have format like

{ "key1": "value1", "key2": "value2", ... }


but i have json string:

{"items":[[24,68,216,34006,32224],[68,177,277,140,2130], |...skip big amount of data....| ,[79606,8500392,0,0,14]],"updated":1475686082000,"columns":["id","buy","sell","supply","demand"]}


I trying to figure out how to read this and get specific amount of data. As example i need to get number in column "buy" and "sell" of specific IDs.

L.B L.B
Answer

According to your json your model should be

public class YourRootObject
{
    public List<List<int>> items { get; set; }
    public long updated { get; set; }
    public List<string> columns { get; set; }
}

and now you can deserialize as

var obj = JsonConvert.DeserializeObject<YourRootObject>(json);

But, Instead of dealing with "updated" value later, I would change the model as below and write a json converter.

public class YourRootObject
{
    public List<List<int>> items { get; set; }
    public DateTime updated { get; set; }
    public List<string> columns { get; set; }
}

public class EpochToDatetimeConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(DateTime);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        var l = (long)reader.Value;
        return new DateTime(1970, 1, 1).AddMilliseconds(l).ToLocalTime();
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }
}

Now you can deserialize as

var obj = JsonConvert.DeserializeObject<YourRootObject>(json, 
                                           new EpochToDatetimeConverter());
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