JavaScriptSerializer.Deserialize - how to change f

Question

Summary: How do I map a field name in JSON data to a field name of a .Net object when using JavaScriptSerializer.Deserialize ?

Longer version: I have the following JSON data coming to me from a server API (Not coded in .Net)

{"user_id":1234, "detail_level":"low"}

I have the following C# object for it:

[Serializable]
public class DataObject
{
    [XmlElement("user_id")]
    public int UserId { get; set; }

    [XmlElement("detail_level")]
    public DetailLevel DetailLevel { get; set; }
}

Where DetailLevel is an enum with "Low" as one of the values.

This test fails:

[TestMethod]
public void DataObjectSimpleParseTest()
{
    JavaScriptSerializer serializer = new JavaScriptSerializer();
    DataObject dataObject = serializer.Deserialize<DataObject>(JsonData);

    Assert.IsNotNull(dataObject);
    Assert.AreEqual(DetailLevel.Low, dataObject.DetailLevel);
    Assert.AreEqual(1234, dataObject.UserId);
}

And the last two asserts fail, since there is no data in those fields. If I change the JSON data to

 {"userid":1234, "detaillevel":"low"}

Then it passes. But I can't change the server's behaviour, and I want the client classes to have well-named properties in the C# idiom. I can't use LINQ to JSON since I want it to work outside of Silverlight. It looks like the XmlElement tags are having no effect. I don't know where I got the idea they were relevant at all, they probably aren't.

How do you do field name mapping in JavaScriptSerializer? Can it be done at all?

Answer 1

Json.NET will do what you want. It supports reading DataContract/DataMember attributes as well as its own to change the property names. Also there is the StringEnumConverter class for serializing enum values as the name rather than the number.

Answer 2

Create a class inherited from JavaScriptConverter. You must then implement three things:

Methods-

1. Serialize
2. Deserialize

Property-

1. SupportedTypes

You can use the JavaScriptConverter class when you need more control over the serialization and deserialization process.

JavaScriptSerializer serializer = new JavaScriptSerializer();
serializer.RegisterConverters(new JavaScriptConverter[] { new MyCustomConverter() });

DataObject dataObject = serializer.Deserialize<DataObject>(JsonData);

Here is a link for further information