在某些字段上使用Json.Net反序列化失败

Question

I try to deserialze Json into ac# object using Json.Net.

c# class:

public class Evaluation
{
    [DataMember(Name = "id")]
    public int Id { get; set; }

    [DataMember(Name = "avg")]
    public string Average { get; set; }

    [DataMember(Name = "median")]
    public string Median { get; set; }

    [DataMember(Name = "teacherID")]
    public int TeacherId { get; set; }

    [DataMember(Name = "evalType")]
    public int EvaluationType { get; set; }
}

Unit Test:

[Test]
[TestCase()]
public void TestParsing()
{
    string json = "{" +
                "\"id\": 439476," +
                "\"avg\": \"69\"," +
                "\"median\": \"75\"," +
                "\"teacherID\": 1," +
                "\"evalType\": 1" +
                "}";

    Evaluation evaluation = JsonConvert.DeserializeObject<Evaluation>(json);

    Assert.IsTrue(evaluation.Average.Equals("69"));
    Assert.IsTrue(evaluation.EvaluationType == 1);
}

This fails because evaluation.Average is null and evaluation.EvaluationType is 0. The other fields are parsed correctly.

Why is this failing?

Answer 1

Setting the DataContract attribute on your class declaration should fix the problem:

[DataContract]
public class Evaluation
{
    [DataMember(Name = "id")]
    public int Id { get; set; }

    [DataMember(Name = "avg")]
    public string Average { get; set; }

    [DataMember(Name = "median")]
    public string Median { get; set; }

    [DataMember(Name = "teacherID")]
    public int TeacherId { get; set; }

    [DataMember(Name = "evalType")]
    public int EvaluationType { get; set; }
}