Deserialize under other class name, or change class name in serialized document c#

Question

I c# would like to change the name of a class that is being persisted through serialization/deserialization (using a binary formatter). If I simply refactor the name to another name, the desirialization of the file won't load (nor did I expect this).

Is there a way to tell the deserializer to load the class under another class-name, so that I can change the name of the class but still keep the old (and big!) file. Or can I serialize using another class name.

Does the question make sense?

Answer 1

No it doesn't make sense, and you can' t deserialize a type to be another type that I know about.

Answer 2

Please take a look at this example, it seems to meet your requirements.

class App  
{  
    [STAThread]  
    static void Main()  
    {  
        Serialize();  
        Deserialize();  
    }  
  
    static void Serialize()  
    {  
        FileStream fs = new FileStream("DataFile.dat", FileMode.Create);  
  
        try  
        {  
            BinaryFormatter formatter = new BinaryFormatter();  
  
            Version1Type obj = new Version1Type();  
            obj.x = 123;  
            formatter.Serialize(fs, obj);  
        }  
        catch (SerializationException e)  
        {  
            Console.WriteLine("Failed to serialize. Reason: " + e.Message);  
            throw;  
        }  
        finally  
        {  
            fs.Close();  
        }  
    }  
  
    static void Deserialize()  
    {  
        Version2Type obj = null;  
  
        FileStream fs = new FileStream("DataFile.dat", FileMode.Open);  
        try  
        {  
            BinaryFormatter formatter = new BinaryFormatter();  
  
            formatter.Binder = new Version1ToVersion2DeserializationBinder();  
  
            obj = (Version2Type)formatter.Deserialize(fs);  
        }  
        catch (SerializationException e)  
        {  
            Console.WriteLine("Failed to deserialize. Reason: " + e.Message);  
            throw;  
        }  
        finally  
        {  
            fs.Close();  
        }  
        Console.WriteLine("Type of object deserialized: " + obj.GetType());  
        Console.WriteLine("x = {0}, name = {1}", obj.x, obj.name);  
    }  
}  
  
[Serializable]  
class Version1Type  
{  
    public Int32 x;  
}  
  
[Serializable]  
class Version2Type : ISerializable  
{  
    public Int32 x;  
    public String name;  
    [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter = true)]  
    void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)  
    {  
        info.AddValue("x", x);  
        info.AddValue("name", name);  
    }  
    [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter = true)]  
    private Version2Type(SerializationInfo info, StreamingContext context)  
    {  
        x = info.GetInt32("x");  
        try  
        {  
            name = info.GetString("name");  
        }  
        catch (SerializationException)  
        {  
            name = "Reasonable default value";  
        }  
    }  
}  
  
sealed class Version1ToVersion2DeserializationBinder : SerializationBinder  
{  
    public override Type BindToType(string assemblyName, string typeName)  
    {  
        Type typeToDeserialize = null;  
  
        String assemVer1 = Assembly.GetExecutingAssembly().FullName;  
        String typeVer1 = "Version1Type";  
  
        if (assemblyName == assemVer1 && typeName == typeVer1)  
        {  
            typeName = "Version2Type";  
        }  
  
        typeToDeserialize = Type.GetType(String.Format("{0}, {1}",  
            typeName, assemblyName));  
  
        return typeToDeserialize;  
    }  
}  

The code comes from a Microsoft documentation, and I deleted the comments to make it look more condensed.
If you want to know more, you can check the original document.

---

If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.