Exception during deserialization with TypeNameHandling = TypeNameHandling.All a json that was saved by browser

[slavapvf]

Exception during deserialization with TypeNameHandling = TypeNameHandling.All a json that was saved by browser

[elgonzo]

I suspect because of the position of $type property

Correct. By default, Newtonsoft.Json detects metadata keywords such as $type only at the beginning of json objects (for performance and memory reasons).

In your situation, you need to explicitly instruct Newtonsoft.Json to read ahead in the json data to look for metadata keywords, at the cost of buffering json data during deserialization. This is done by setting the JsonSerializerSettings MetadataPropertyHandling property to ReadAhead. (https://www.newtonsoft.com/json/help/html/SerializationSettings.htm#MetadataPropertyHandling)

[slavapvf]

Thank you for solution. It is working now. Would be nice to have a hint on TypeNameHandling with recommendation for MetadataPropertyHandling because the exception can happens occasionally.