Decode JSON Object in C# without prior knowledge of type

Question

I have some working code:

String objstr = "{\"m_children\":[{\"m_children\":null,\"m_name\":\"child0\"},{\"m_children\":null,\"m_name\":\"child1\"}],\"m_name\":\"Root\"}";
byte[] byteArr = Encoding.ASCII.GetBytes(objstr);
MemoryStream ms = new MemoryStream(byteArr);
DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(Node));

Node obj = (Node)ser.ReadObject(ms);

What bugs me is that I have to know the type of the object contained in the string before I decode it. I wanted to send an object encoded in JSON over a TCP pipe, and not have to send extra information about what type the object is.

json can only serialize plain objects. can't you use some other form of serialization that allows typing? — Einacio, Aug 24 '11 at 13:27
[Dynamic?](http://msdn.microsoft.com/en-us/library/dd264736.aspx) @einacio, they specifically asked to "not have to send extra information about what type the object is", which, say, xsd would be. — bzlm, Aug 24 '11 at 13:27
so @Almo want magic typing on a static typed language. could send the type as an extra data in the json, but i don't know if c++ can create objets using strings instead of classname php-style — Einacio, Aug 24 '11 at 13:39
I was wondering why the serializer doesn't include any type info in its output. I found a place where the .net serializer will, but it seems to be non-standard and won't work with serializers outside .net. And I'm not in C++. — Almo, Aug 24 '11 at 14:48

score 3 · Accepted Answer · edited May 23 '17 at 12:24

3

With .NET 4.0 you can use dynamic objects. Why not try out this solution from another question: Deserialize JSON into C# dynamic object?

edited May 23 '17 at 12:24

Community

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answered Aug 24 '11 at 13:30

Roy Goode

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Thanks, I'll look at that once we upgrade to VS2010. – Almo Aug 24 '11 at 13:40
I think if you're not using VS2010, you'll need to create your own serializer/deserializer using collections, such as Dictionary objects to represent the JSON field names and values. – Roy Goode Aug 24 '11 at 13:45

score 0 · Answer 2 · answered Aug 25 '11 at 13:43

Additional info:

http://www.codeproject.com/KB/IP/fastJSON.aspx

When this library encodes JSON, it gives enough info for completely automatic reparsing.

This doesn't suit my purpose that well though, since it includes a bunch of C#-specific info, and we're working cross-language here.

Decode JSON Object in C# without prior knowledge of type

2 Answers2