C# serialization to PlayerPrefs -> exceptions only in Editor!

Unity Engine
1

This is kinda bizarre! Here is my code to serialize a class marked as [Serializable] to PlayerPrefs__. It’s working perfectly on my player build (iOS). I can even rearrange/add properties to the class, then compile and the runtime is still able to deserialize and instantiate the object correctly. Sweet.__

The bizarre part is it doesn’t work in the Editor. I am getting this exception on Load(). Why would it work in the runtime but not in the editor? Any ideas oh C# gurus? Could the [Serializable] flag on my class be mixing up the Editor? Thanks!

using UnityEngine;
using System;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;

public class PlayerPrefsSerializer  
{
	private static BinaryFormatter bf = new BinaryFormatter ();
		
	public static void Save (string prefKey, object serializableObject)
	{
		if (serializableObject == null)
			return;
		Debug.Log (string.Format ("Saving: {0} => {1}", prefKey, serializableObject.GetType ()));
		MemoryStream memoryStream = new MemoryStream ();
		bf.Serialize (memoryStream, serializableObject);
		string serializedData = System.Convert.ToBase64String (memoryStream.ToArray ());
		PlayerPrefs.SetString (prefKey, serializedData);
		Debug.Log (string.Format ("Saved serialized data {0}", serializedData));
	}
	
	public static object Load (string prefKey)
	{
		if (!PlayerPrefs.HasKey (prefKey))
			return null;
		
		string serializedData = PlayerPrefs.GetString (prefKey, String.Empty);
		if (serializedData == String.Empty)
			return null;
		
		Debug.Log (string.Format ("Loading serialized data {0} {1}", prefKey, serializedData));		
		MemoryStream dataStream = new MemoryStream (System.Convert.FromBase64String (serializedData));
		object result = bf.Deserialize (dataStream);		
		Debug.Log (string.Format ("Loaded: {0} => {1}", prefKey, result.GetType ()));				
		return result;
	}
}
2

I’m guessing because it’s using the BinaryFormatter. I haven’t used that much (I’m an XmlSerializer kinda guy), but from what I understand it’s pretty tied to assemblies and their versions, and from the looks of it the Editor uses temporary/on-the-fly-compiled assemblies, so maybe that’s the issue. Can you switch it up to XmlSerialization instead of using a BinaryFormatter?

3

Yes, I suspected the same- it’s really the only explanation I could think of. I was trying to avoid depending on XML (and adding more .dlls to my player build). But I should definitely try that for the sake of understanding what’s going on.

4

Or maybe I could use XML serialization in the Editor, and BinaryFormatter in the player build!!

5

I was just thinking the same thing; you could likely use the compiler flags (http://unity3d.com/support/documentation/Manual/Platform%20Dependent%20Compilation.html) to target either platform. Just double-check your output size so that it doesn’t include the extra DLLs for non-applicable builds.

6

Excellent- the XML serialization is working in the editor, and the compiler flags to produce my optimal code for player build. Thanks

7

If you included the XML serialization in your other builds, does it inflate the size much? I only ask because if you plan to issue new versions of your game but still be backward-compatible with legacy save data, you might possibly run into issues for similar reasons.

8

Yes, just using XMLSerializer adds about 6MB of .dlls to the build! (System.Xml plus various other dependencies)
Also this note from the manual:

So I am going to go with the BinaryFormatter method on iOS- it apparently only adds a .dll about 8KB: System.Core.dll
Also going to tag the PlayerPref key with the version number of my app, so that I won’t accidentally try to deserialize incompatible data. I will of course have to write a migration method if the classes change from version to version but that’s OK.

9

Ahh, good good. Interesting that it’s adding 6mb for you. I’m using the XmlSerializer and my total web player unity size (including all assets/code) is only 933kb.