Comments on: BinaryFormatter on iOS

By: Sam

Sam — Thu, 12 Mar 2015 13:29:50 +0000

I looked into this a bit. The BinaryFormatter (and other serialisers too, I assume) ends up calling an internal method in Generic.Dictionary called Do_CopyTo. It seems that for some reason Mono isn’t able to generate the code for this method ahead-of-time, so instead it tries to generate it at runtime. Looking at Do_CopyTo, I can’t see what would be confusing it. There’s a delegate argument, but it has all the type information so in theory it should have everything it needs. I tried forcing the compiler to generate a concrete class to work around it but I just couldn’t get it to generate it.

To work around this you can use the Collections.Hashtable instead of the generic dictionary. It’s not as nice since it isn’t type safe and you have to cast everywhere, but at least it works.

I thought the issue might have been the nested generics, but replacing the List<> with an ArrayList doesn’t help.

By: Yuriy

Yuriy — Thu, 12 Mar 2015 07:35:10 +0000

Hi, and thank you for a response. The type I’m storing in the List is from a class I made. The dictionary definition looks like this : Dictionary, where Upgrade data is :
[Serializable]
public class UpgradeData
{
public bool lockStatus;
public bool purchased;

}
and then the class that handles the Dictionary looks like this:
[Serializable]
public class CharacterUpgradeList
{

private UpgradeData[] _upgrade_Data;
private List[] upgData;

public Dictionary upgradeList;
public CharacterUpgradeList()
{
upgData = new List[4];
for (int i = 0; i < upgData.Length; i++)
{
upgData[i] = new List {
new UpgradeData(),
new UpgradeData(),
new UpgradeData(),
new UpgradeData(),
new UpgradeData(),
new UpgradeData()
};
}

upgradeList = new Dictionary
{
{“Man”,upgData[0]},
{“Woman”,upgData[1]},
{“Boy”,upgData[2]},
{“Girl”,upgData[3]}

};
}
}

By: Sam

Sam — Thu, 12 Mar 2015 07:16:41 +0000

I’m not exactly sure. There’s evidently some other part of Mono that is trying to generate code to perform the serialisation. Are you getting the “Attempting to JIT compile method” exception? What types are you storing in your List in the Dictionary?

By: Yuriy

Yuriy — Thu, 12 Mar 2015 07:03:43 +0000

Hi. Using this tip helped me serialize all my objects on a Ios device. But recently I had to add a Dictionary data structure to my project. It is the flowing: Dictionary. This does not serialize on Ios and fires a JIT exception. Why is this happening and how can I get around it ?