Is it possible to deserialize inline arrays with Json.NET? - json.net

Question

Let me try to simplify my question by extracting and abstracting relevant information from a complex object and large JSON text.
Class Foo()
{
string Name;
Version[] versions;
}
JsonText(converted from XML) can be something like this:
"Foo": {
"Name": "test",
"versions": {
"Major": "1",
"Minor": "1"
},
"versions": {
"Major": "2",
"Minor": "1"
},
"versions": {
"Major": "3",
"Minor": "1"
}
}
or the following:
"Foo": {
"Name": "test",
"versions": {
"Major": "1",
"Minor": "1"
}
}
JsonConvert.DeserializeObject(JsonText) results in:
Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'Version[]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
Is it possible to do this desrialization?

Answer 1

Updated based on commment
Your Json doesn't look valid. A Json needs to be enclosed with "[" "]". For example,
[ "Ford", "BMW", "Fiat" ]
If you are allowed to modify your Json, You could modify the Json as following
{
"Foo":
{
"Name": "test",
"versions": [
{
"Major": "1",
"Minor": "1"
},
{
"Major": "2",
"Minor": "1"
},
{
"Major": "3",
"Minor": "1"
}]
}
}
Based on your comment, you would like to avoid the Json Array Syntax if there is only a single element. On other cases, you would like to stick to Array Syntax. In such scenario,you could write a Custom Json Converter.
class CustomConverter<T> : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return (objectType == typeof(List<T>));
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
JToken token = JToken.Load(reader);
if (token.Type == JTokenType.Array)
{
return token.ToObject<List<T>>().ToArray();
}
return new List<T> { token.ToObject<T>() }.ToArray();
}
public override bool CanWrite
{
get { return false; }
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
You can decorate your class with JsonConverter attribute to use the Custom Json Converter.
class Wrapper
{
public Foo Foo{get;set;}
}
class Foo
{
[JsonProperty("Name")]
public string Name{get;set;}
[JsonProperty("versions")]
[JsonConverter(typeof(CustomConverter<Version>))]
public Version[] versions{get;set;}
}
Now you can deserialize as
var result =JsonConvert.DeserializeObject<Wrapper>(str);
This would now work, if you use either of following Json definition.
{
'Foo':
{
'Name': 'test',
'versions': [
{
'Major': '1',
'Minor': '1'
},
{
'Major': '2',
'Minor': '1'
},
{
'Major': '3',
'Minor': '1'
}]
}
}
Single Version (Without Array syntax)
{
'Foo':
{
'Name': 'test',
'versions':
{
'Major': '1',
'Minor': '1'
}
}
}