使用 Json.Net 反序列化在某些字段上失败

Question

我尝试使用 Json.Net 将 Json 反序列化为 c# 对象。

c#类：

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; }
}

单元测试：

[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);
}

这会失败，因为evaluation.Average 为null，且evaluation.EvaluationType 为0。其他字段解析正确。

为什么会失败？

Answer 1

在类声明中设置DataContract 属性应该可以解决问题：

[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; }
}