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Deserializing problem at runtime, InvalidCastException
I was just messing around with serialization, when a strange error was popping up, only at runtime though. It says:
InvalidCastException: Cannot cast from source type to destination type. MyScript.Load ()
The adressed C# script (MyScript) contains this code:
public static int highscore = 0; //saved Highscore
public static int collectedPoints = 0; //Points collected on this account
public static int lifetimeScore = 0; //count of all points ever collected
public static void Load()
{
if(File.Exists(Application.persistentDataPath + "/saveFiles.xyz"))
{
BinaryFormatter bf = new BinaryFormatter();
FileStream file = File.Open(Application.persistentDataPath + "/saveFiles.xyz", FileMode.Open);
SaveValues.highscore = (int)bf.Deserialize(file);
SaveValues.collectedPoints = (int)bf.Deserialize(file);
SaveValues.lifetimeScore = (int)bf.Deserialize(file);
file.Close();
}
}
public static void Save()
{
BinaryFormatter bf = new BinaryFormatter();
FileStream file = File.Create (Application.persistentDataPath + "/saveFiles.xyz");
bf.Serialize(file, SaveValues.highscore);
bf.Serialize(file, SaveValues.collectedPoints);
bf.Serialize (file, SaveValues.lifetimeScore);
file.Close();
}
public static void Reset()
{
if (File.Exists (Application.persistentDataPath + "/saveFile.xyz"))
{
File.Delete (Application.persistentDataPath + "/saveFile.xyz");
Application.LoadLevel(0);
}
}
SavedValues is the class containing these variables. I think the error is pointing towards the "SavedValues.lifetimeScore"-line in the Load()-function. What am i missing?
Thanks in advance.
Answer by Bunny83 · Nov 02, 2015 at 03:10 AM
Deserialize will deserialize an object graph from the given stream. It isn't ment to be used several times in a row. You should serialize one thing and that's what you will get back when you deserialize the stream. Usually you would use a data class like this one:
[System.Serializable]
public class SaveData
{
public int highscore = 0;
public int collectedPoints = 0;
public int lifetimeScore = 0;
}
You can either create a temporary instance of that class, assign your values to the fields and then serialize it, or directly replace your static variables with a single variables to an instance of that SaveData class.
public static SaveData data = new SaveData();
That way you always store the data directly into the instance. To access a value you would need to use
MyScript.data.highscore = 42;
// instead of
MyScript.highscore = 42;
Now you can simply serialize and deserialize your SaveData class. When you deserialize it you will simple replace the current instance with the deserialized version:
data = (SaveData)bf.Deserialize(file);
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