Deserializing heterogenous JSON array into covariant List<> using Json.NET

Question

I have a JSON-array containing objects of different types with different properties. One of the properties is called \"type\" and determines the type of the array item. Here

Answer 1

It could also be implemented it with my JsonSubTypes library in a declarative way:

[JsonConverter(typeof(JsonSubtypes), "valueType")]
[JsonSubtypes.KnownSubType(typeof(IntItem), "int")]
[JsonSubtypes.KnownSubType(typeof(StringItem), "string")]
public abstract class Item
{
    public string ValueType { get; set; }

    [JsonProperty("valueTypeId")]
    public int ValueTypeId { get; set; }

    [JsonProperty("name")]
    public string Name { get; set; }

    public override string ToString()
    {
        return "Base object, we dont' want base created ValueType=" + this.ValueType + "; " + "name: " + Name;
    }
}

public class StringItem : Item
{
    [JsonProperty("value")]
    public string Value { get; set; }

    [JsonProperty("numberChars")]
    public int NumberCharacters { get; set; }

    public override string ToString()
    {
        return "StringItem object ValueType=" + this.ValueType + ", Value=" + this.Value + "; " +
               "Num Chars= " + NumberCharacters;
    }
}

public class IntItem : Item
{
    [JsonProperty("value")]
    public int Value { get; set; }

    public override string ToString()
    {
        return "IntItem object ValueType=" + this.ValueType + ", Value=" + this.Value;
    }
}

[TestMethod]
public void Demo()
{
    // json string
    var json =
        "[{\"value\":5,\"valueType\":\"int\",\"valueTypeId\":1,\"name\":\"numberOfDups\"}," +
        "{\"value\":\"some thing\",\"valueType\":\"string\",\"valueTypeId\":1,\"name\":\"a\",\"numberChars\":11}," +
        "{\"value\":2,\"valueType\":\"int\",\"valueTypeId\":2,\"name\":\"b\"}]";

    var result = JsonConvert.DeserializeObject>(json);

    Assert.AreEqual("IntItem object ValueType=int, Value=5", result[0].ToString());
    Assert.AreEqual("StringItem object ValueType=string, Value=some thing; Num Chars= 11", result[1].ToString());
    Assert.AreEqual("IntItem object ValueType=int, Value=2", result[2].ToString());
}