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PODeserializing JSON when sometimes array and sometimes object
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  1. PODeserializing JSON when sometimes array and sometimes object
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    copied!<p>I'm having a bit of trouble deserializing data returned from Facebook using the JSON.NET libraries.</p> <p>The JSON returned from just a simple wall post looks like:</p> <pre><code>{ "attachment":{"description":""}, "permalink":"http://www.facebook.com/permalink.php?story_fbid=123456789" } </code></pre> <p>The JSON returned for a photo looks like:</p> <pre><code>"attachment":{ "media":[ { "href":"http://www.facebook.com/photo.php?fbid=12345", "alt":"", "type":"photo", "src":"http://photos-b.ak.fbcdn.net/hphotos-ak-ash1/12345_s.jpg", "photo":{"aid":"1234","pid":"1234","fbid":"1234","owner":"1234","index":"12","width":"720","height":"482"}} ], </code></pre> <p>Everything works great and I have no problems. I've now come across a simple wall post from a mobile client with the following JSON, and deserialization now fails with this one single post:</p> <pre><code>"attachment": { "media":{}, "name":"", "caption":"", "description":"", "properties":{}, "icon":"http://www.facebook.com/images/icons/mobile_app.gif", "fb_object_type":"" }, "permalink":"http://www.facebook.com/1234" </code></pre> <p>Here is the class I am deserializing as:</p> <pre><code>public class FacebookAttachment { public string Name { get; set; } public string Description { get; set; } public string Href { get; set; } public FacebookPostType Fb_Object_Type { get; set; } public string Fb_Object_Id { get; set; } [JsonConverter(typeof(FacebookMediaJsonConverter))] public List&lt;FacebookMedia&gt; { get; set; } public string Permalink { get; set; } } </code></pre> <p>Without using the FacebookMediaJsonConverter, I get an error: Cannot deserialize JSON object into type 'System.Collections.Generic.List`1[FacebookMedia]'. which makes sense, since in the JSON, Media is not a collection. </p> <p>I found this post which describes a similar problem, so I've attempted to go down this route: <a href="https://stackoverflow.com/questions/4572732/deserialize-json-sometimes-value-is-an-array-sometimes-blank-string">Deserialize JSON, sometimes value is an array, sometimes &quot;&quot; (blank string)</a></p> <p>My converter looks like:</p> <pre><code>public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) { if (reader.TokenType == JsonToken.StartArray) return serializer.Deserialize&lt;List&lt;FacebookMedia&gt;&gt;(reader); else return null; } </code></pre> <p>Which works fine, except I now get a new exception:</p> <p>Inside JsonSerializerInternalReader.cs, CreateValueInternal(): Unexpected token while deserializing object: PropertyName</p> <p>The value of reader.Value is "permalink". I can clearly see in the switch that there's no case for JsonToken.PropertyName. </p> <p>Is there something I need to do differently in my converter? Thanks for any help. </p>
 

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