Nsryjdtyk

I am sending a GET request to a Rest API that returns some JSON in two different formats (based on some external setting that I can't influence).
I can either receive:

"content": {

    "fields": [

     {

         "name": "test1",

         "value": 1

     },

     {

         "name": "test2",

         "value": "test"

     },

     {

         "name": "test3",

         "value": "test",

         "links": [...]

     }

   ]

}

or

"content": {

  "test1": 1,

  "test2": "test",

  "test3": "test"

}

You can see that I receive either a list of objects containing name and value properties (along with some other properties like links), or I receive a single object containing key-value pairs as in a Dictionary. I now want to know if there is a way to conditionally deserialize the JSON into a class with Dictionary<string, string> and List<Field> properties like this:

[Serializable]

public class Content

{

    /// <summary>

    /// The Type of the Content

    /// </summary>

    public string _Type { get; set; }



    public Dictionary<string, string> Dictionary { get; set; }



    public List<Field> Fields { get; set; }

}

and fill either the dictionary or the list of fields depending on the JSON.

You can handle this situation by creating a custom JsonConverter for your Content class as shown below. It works by loading the content portion of the JSON into a JObject and checking for the presence of the fields property to determine how to populate the Content instance.

public class ContentConverter : JsonConverter

{

    public override bool CanConvert(Type objectType)

    {

        return objectType == typeof(Content);

    }



    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

    {

        JObject jo = JObject.Load(reader);

        Content content = new Content();

        if (jo["fields"] != null)

        {

            // if the fields property is present, we have a list of fields

            content.Fields = jo["fields"].ToObject<List<Field>>(serializer);

            content._Type = "Fields";

        }

        else

        {

            // fields property is not present so we have a simple dictionary

            content.Dictionary = jo.Properties().ToDictionary(p => p.Name, p => (string)p.Value);

            content._Type = "Dictionary";

        }

        return content;

    }



    public override bool CanWrite

    {

        get { return false; }

    }



    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

    {

        throw new NotImplementedException();

    }

}

I was not sure how you wanted to handle the _Type property, so I just set it to either "Fields" or "Dictionary" to indicate which property was populated. Feel free to change it to suit your needs.

To use the converter, just add a [JsonConverter] attribute to your Content class like this:

[JsonConverter(typeof(ContentConverter))]

public class Content

{

    ...

}

Here is a working demo: https://dotnetfiddle.net/geg5fA