WP7 tombstoning, saving sprite into Current state not working - windows-phone-7

Question

I am working on a WP7 game. I am using Game state managment (http://create.msdn.com/en-US/education/catalog/sample/game_state_management , but I think its not important ) I have problem with saving data into
Microsoft.Phone.Shell.PhoneApplicationService.Current.State
if I put there sprite in this method
public override void Deactivate()
{
#if WINDOWS_PHONE
Microsoft.Phone.Shell.PhoneApplicationService.Current.State["Score"] = Score;
Microsoft.Phone.Shell.PhoneApplicationService.Current.State["cloudSprite"] = cloudSprite;
#endif
base.Deactivate();
}
there is nothing in
Microsoft.Phone.Shell.PhoneApplicationService.Current.State
in activate method. However if I remove cloudSprite and put there only Score which is int it works fine. I dont know whats wrong maybe it cant handle more complex objects. I tried also float doubel, it all works. But if I put there something more complex it doesnt work. What do you think ?
EDIT
This is my sprite class. I dont know how to make it serializable. I have added there [DataContractAttribute()] and [DataMember] but its not working
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Content;
using System.Runtime.Serialization;
using System.IO;
namespace GameStateManagementSample.GameObjects
{
[DataContractAttribute()]
public class Sprite
{
[DataMember]
public Vector2 Position;
[DataMember]
public Vector2 Size;
[DataMember]
public Texture2D Texture;
[DataMember]
public Rectangle Rect
{
get
{
return new Rectangle((int)Position.X, (int)Position.Y, (int)Size.X, (int)Size.Y);
}
}
public Sprite(Vector2 position)
{
Position = position;
}
public Sprite(Vector2 position, Vector2 size)
{
Position = position;
Size = size;
}
public Sprite(Vector2 position, Texture2D texture)
{
Position = position;
Texture = texture;
Size = new Vector2(Texture.Width, Texture.Height);
}
public void LoadContent(string assetName, ContentManager content)
{
Texture = content.Load<Texture2D>(assetName);
if (Size == Vector2.Zero)
Size = new Vector2(Texture.Width, Texture.Height);
}
public virtual void Draw(SpriteBatch spriteBatch)
{
//spriteBatch.Draw(Texture, Rect, Color.White);
spriteBatch.Draw(Texture, Position, Color.White);
}
public virtual void Draw(SpriteBatch spriteBatch, Rectangle TexturePositionInSpriteSheet, Color color)
{
spriteBatch.Draw(Texture, Position, TexturePositionInSpriteSheet, color);
}
public bool Intersects(Vector2 point)
{
if (point.X >= Position.X && point.Y >= Position.Y && point.X <= Position.X + Size.X && point.Y <= Position.Y + Size.Y)
return true;
else return false;
}
public bool Intersects(Rectangle rect)
{
return Rect.Intersects(rect);
}
public static void Serialize(Stream streamObject, object objForSerialization)
{
if (objForSerialization == null || streamObject == null)
return;
DataContractSerializer ser = new DataContractSerializer(objForSerialization.GetType());
ser.WriteObject(streamObject, objForSerialization);
}
public static object Deserialize(Stream streamObject, Type serializedObjectType)
{
if (serializedObjectType == null || streamObject == null)
return null;
DataContractSerializer ser = new DataContractSerializer(serializedObjectType);
return ser.ReadObject(streamObject);
}
}
}

Answer 1

Objects added to the State collection are serialized with the DataContractSerializer. Ensure that anything you're saving there can be serialized that way.
Any serialization errors are silently ignored.
Update
Here's a simplified version of your Sprite object:
[DataContract]
public class Sprite
{
[DataMember]
public Vector2 Position;
[DataMember]
public Vector2 Size;
[DataMember]
public Texture2D Texture;
public Sprite()
{
}
public Sprite(Vector2 position)
{
Position = position;
}
public Sprite(Vector2 position, Vector2 size)
{
Position = position;
Size = size;
}
public Sprite(Vector2 position, Texture2D texture)
{
Position = position;
Texture = texture;
Size = new Vector2(Texture.Width, Texture.Height);
}
}
And here's an example of it being serialized and deserialized:
// Sprite serialization test
var sprite1 = new Sprite(new Vector2(12.34f, 56.78f));
Sprite sprite2;
using (var memStr = new MemoryStream())
{
var serializer = new DataContractSerializer(typeof(Sprite));
serializer.WriteObject(memStr, sprite1);
memStr.Position = 0;
var sr = new StreamReader(memStr);
var serialized = sr.ReadToEnd();
// serialized now looks like
// <Sprite xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/MiscExperiments"><Position xmlns:d2p1="http://schemas.datacontract.org/2004/07/Microsoft.Xna.Framework"><d2p1:X>12.34</d2p1:X><d2p1:Y>56.78</d2p1:Y></Position><Size xmlns:d2p1="http://schemas.datacontract.org/2004/07/Microsoft.Xna.Framework"><d2p1:X>0</d2p1:X><d2p1:Y>0</d2p1:Y></Size><Texture xmlns:d2p1="http://schemas.datacontract.org/2004/07/Microsoft.Xna.Framework.Graphics" i:nil="true" /></Sprite>
memStr.Position = 0;
sprite2 = (Sprite)serializer.ReadObject(memStr);
// sprite2 now contains the same as
// sprite2.Position = { X:12.34, Y:56.78 }
}

Answer 2

I believe that you get the ArgumentOutOfRangeException which is silently ignored if you aren't debugging (in which case the exception is thrown). The items stored in the State dictionary need to be serializable. Try storing that sprite somehow and saving only a link (source) to the sprite in the state dictionary.