Serialization - C# Data Types

Question

I have an object that I wish to serialize into JSON, but instead of each property having its associated value, I'd rather have each property have its associated type.

For example, I have the following class:

public class Student
{
    public string Name { get; set; }
    public int Age { get; set; }
    public DateTime? DateOfBirth { get; set; }
    public bool IsMarried { get; set; }
}

The resulting JSON I would like to have looks like this

{
    "Student:" {
       "Name": "String",
       "Age": "Int",
       "DateOfBirth": "DateTime",
       "IsMarried": "Boolean"
    }
}

Is there a way that I can setup a JsonSerializer to serialize each property's type instead of its value?

Are you looking for a json schema generator?

Zohar Peled
– Zohar Peled

2018-02-21 15:30:30 +00:00
Commented Feb 21, 2018 at 15:30 — Zohar Peled
– Zohar Peled, Commented Feb 21, 2018 at 15:30

Ian H. · Accepted Answer · 2018-02-21 15:31:40Z

Using information from this answer to build a custom JsonSerializer, you can modify the WriteJson method to specify the information that you want to write.

Building a custom JsonSerializer requires creating a new class and deriving it from JsonSerializer, then override any methods that you are interested in customizing.

public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
    if (value == null)
    {
        serializer.Serialize(writer, null);
        return;
    }

    var properties = value.GetType().GetProperties();

    writer.WriteStartObject();

    foreach (var property in properties)
    {
        // Write the property name
        writer.WritePropertyName(property.Name);
        // Get the value of the property and get the type
        serializer.Serialize(writer, property.GetValue(value, null).GetType());
    }

    writer.WriteEndObject();
}

Delfino · Accepted Answer · 2018-02-21 16:12:32Z

Modifying Ian H.'s answer I was able to create a custom JsonConverter to handle writing property types to JSON.

public class CustomConverter : JsonConverter
{
    private readonly Type[] _types;

    public CustomConverter(params Type[] types)
    {
        _types = types;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        if (value == null)
        {
            serializer.Serialize(writer, null);
            return;
        }

        var properties = value.GetType().GetProperties();

        writer.WriteStartObject();

        foreach (var property in properties)
        {
            // Write the property name
            writer.WritePropertyName(property.Name);
            // Get the property type name of the property
            serializer.Serialize(writer, property.PropertyType.Name);
        }

        writer.WriteEndObject();
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }

    public override bool CanConvert(Type objectType)
    {
        return _types.Any(t => t == objectType);
    }
}

Using another custom class of mine, witch each property being a string, upon trying to convert a fresh, new instance of the class every property value is null, so calling property.GetValue(value, null).GetType() throws a NullReferenceException.

Because of this I substituted that line of code with property.PropertyType.Name, which works perfectly!

Nice! Didn't know PropertyName existed until now, great job on finding out!
What are the writer.WriteStartObject() and writer.WriteEndObject() lines for?
AFAIK they write the indicators for the beginning { and the end } to the JsonWriter.

Collectives™ on Stack Overflow

Serialization - C# Data Types

2 Answers 2

Comments

3 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

3 Comments

Linked

Related