Deserialize object into assembly that is now signed and versioned

Question

I used to serialize a treeview with the BinaryFormatter (c#). The Assembly that did just that and which contains the all the serializable classes has now a strong name and i

Answer 1

You can use a SerializationBinder to solve this:

private class WeakToStrongNameUpgradeBinder : SerializationBinder
{
    public override Type BindToType(string assemblyName, string typeName)
    {
        try 
        {
            //Get the name of the assembly, ignoring versions and public keys.
            string shortAssemblyName = assemblyName.Split(',')[0];
            var assembly = Assembly.Load(shortAssemblyName);
            var type = assembly.GetType(typeName);
            return type;
        }
        catch (Exception)
        {
            //Revert to default binding behaviour.
            return null;
        }
    }
}

Then

var formatter = new BinaryFormatter();
formatter.Binder = new WeakToStrongNameUpgradeBinder();

Voila, your old serialized objects can be deserialized with this formatter. If the type have also changed you can use a SerializationSurrogate to deserialize the old types into your new types.

As others have mentioned, doing your own serialization rather than relying on IFormatter is a good idea as you have much more control over versioning and serialized size.