Deserializing an object, a value is not deserialized

Question

This is my class:

namespace myclass
{
    [Serializable]
    public class BasicGameObject : GameObject
    {
      protected Shadow shadow_ = null;
      protected bool shadow_enabled_ = false;

      protected Dictionary<string, AnimationManager> animations_ = new Dictionary<string, AnimationManager>();
      protected Dictionary<string, string> loaded_textures_ = new Dictionary<string, string>();

      protected string current_animation_;

      protected int frame_width_;
      protected int frame_height_;

//Costructor and other methods
//...

    [OnDeserialized]
    private void OnDeserialized(StreamingContext context)
    {
        Console.WriteLine("BasicGameObject");
        foreach (KeyValuePair<string, AnimationManager> anim in animations_)
        {
            animations_[anim.Key].Reload(Loader.GameObjectTexturesList[loaded_textures_[anim.Key]]);
        }
    }

When I deserialize this object, I need it to reload every texture stored in "animations_". If I put a breakpoint on Console.WriteLine("BasicGameObject");, and click on anim, the debugger shows me that anim's Count is at 0, but every other variable has the right value. (I'm sure that while saving, it wasn't at 0)

What's the problem?

How I load the object (SERIALIZATIONOBJECT_ just contains a list of BasicGameObject):

    IFormatter formatter = new BinaryFormatter();
    SERIALIZATIONOBJECT_ = (SerializationObject)formatter.Deserialize(stream);
    stream.Close();

After this, (and after OnDeserialized call!), If i do some test, I see that anim of my object, has the right value. Why here and not inside "OnDeserialized"?

I just want to note that before I was using the same identical function that now is in OnDeserialized without the attribute, but just as a function, and I was calling it after deserialization. I saw the possibility di automatize it and I thought it was good. Maybe it hides something.

Is AnimationManager marked as Serializable? You may want to make it so, if it isn't already. — TyCobb, Jan 15 '14 at 17:33
I'm not sure at all, but I believe that the serialization only affect to the public attributes. — superarce, Jan 16 '14 at 09:02

score 2 · Answer 1 · answered Jan 16 '14 at 09:16

2

XmlSerializer only serializes and deserializes public fields and properties.

See the MSDN documentation :

XML serialization is the process of converting an object's public properties and fields to a serial format (in this case, XML) for storage or transport. [...]

You may want to use a data transfer object (DTO) in this situation. The DTO is an internal class which holds all the data for your game object as public fields or properties which can be serialized and deserialized. Then simply aggregate the DTO to your game object and access the data via the DTO.

answered Jan 16 '14 at 09:16

helb

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Maybe I am missing something, but I'm not using XML serialization, but the binary formatter... When I open the output file I see some word but a lot of unknown symbols, not the typic XML code. – Francesco Bonizzi Jan 16 '14 at 12:32
@misiMe Sorry, my bad. I'll leave this answer and pout another one concerning OnDeserialized. – helb Jan 16 '14 at 12:53

helb · Accepted Answer · 2014-01-16T13:13:06.173

2

According to the MSDN documentation for the OnDeserialized attribute:

When applied to a method, specifies that the method is called immediately after deserialization of an object in an object graph. The order of deserialization relative to other objects in the graph is non-deterministic.

the method OnDeserialize is called after the object was deserialized but (to my understanding) not necessarily after all aggregated objects were also deserialized.

You are performing an operation in your OnDeserialized method which uses the aggregated animations_ dictionary containing AnimationManager objects which must also be deserialized. If OnDeserialized is called before the AnimationManager objects are deserialized, it would explain the symptoms you described.

Best you call the method yourself and remove the OnDeserialized attribute.

edited Jan 16 '14 at 13:13

answered Jan 16 '14 at 12:52

helb

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8
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58

1

Is there a way to specific an "order" of deserialization? In that way I could choose an order due to dependencies of every object. – Francesco Bonizzi Jan 16 '14 at 13:18
@misiMe You may find a way by poking around long enough but if the documentation says the order is non-deterministic you probably don't have much of a choice (if you want your code to work reliably). – helb Jan 16 '14 at 13:20

Deserializing an object, a value is not deserialized

2 Answers2