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POJSON.NET deserialize to object with Type parameter
 

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    <p>I have the following problem which I am unable to solve:</p> <p>I have different classes which all implement an interface named <code>IProtocol</code>. The are named, for now, <code>SimpleProtocol</code>, <code>ParallelProtocol</code>. I wanted to persist those object so I used JSON.NET and everything works fine. Except when I am trying to deserialize them it works perfectly when I know the type they are supposed to be, for instance:</p> <pre><code>SimpleProtocol p = JsonConvert.DeserializeObject&lt;SimpleProtocol&gt;(myJsonData); </code></pre> <p>However, I am now in a situation where I want to load the JSON data and get an <code>IProtocol</code> back, but that is, understandably, not allowed by JSON; E.g., something like this does <strong>not</strong> work:</p> <pre><code>IProtocol p1 = JsonConvert.DeserializeObject&lt;IProtocol&gt;(myJsonData); // does not work IProtocol p2 = (IProtocol)JsonConvert.DeserializeObject(myJsonData); // also, does not work </code></pre> <p>So, looking up the <a href="http://james.newtonking.com/projects/json/help/index.html?topic=html/Overload_Newtonsoft_Json_JsonConvert_DeserializeObject.htm">API</a> I found this method signature:</p> <pre><code>public static Object DeserializeObject( string value, Type type ) </code></pre> <p>which looks just like the thing I needed, so trying out by also persisting the type in a string and retrieving it:</p> <pre><code>// test Type protocolType = Type.GetType("MyApp.Protocols.SimpleProtocol"); IProtocol p1 = JsonConvert.DeserializeObject(myJsonData, protocolType); </code></pre> <p>I get an error that it is impossible to cast a <code>Newtonsoft.Json.Linq.JObject</code> to <code>IProtocol</code>. This is weird and I don't know how to solve this.</p> <p>It is impossible to pass the Type object in a generic method, so I am basically stuck here. Is there a method to solve this, preferably without using Reflection? It looks to me that this is a perfectly normal use case.</p> <p>What I can do, but it seems a bit 'dirty' to me, is to create a simple wrapper class which holds an IProtocol instance in it and serialize / deserialize that?</p>
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    1. COAre you deserializing a single element or a collection of them?
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    2. COYou might want to take a look at these questions, and see if they help: [Casting interfaces for deserialization in JSON.NET](http://stackoverflow.com/q/5780888/164966), [How to implement custom JsonConverter in JSON.NET to deserialize a List of base class objects](http://stackoverflow.com/q/8030538/164966), [Using Json.NET converters to deserialize properties](http://stackoverflow.com/q/2254872/164966).
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    3. COThanks for your tips, I've read them through, but my solution proved to be different (see below).
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