Here's a simplified version (no subclassing):

 MemoryStream fs = new MemoryStream();
BinaryFormatter formatter = new BinaryFormatter();

SurrogateSelector ss = new SurrogateSelector();
CanvasSurrogate CanvasSurrogate = new CanvasSurrogate();
ss.AddSurrogate(typeof(Canvas),new StreamingContext(StreamingContextStates.All),CanvasSurrogate);
formatter.SurrogateSelector = ss;

Canvas x = new Canvas();
x.Name = "Fred";
formatter.Serialize(fs, x);
fs.Position = 0;
Canvas y = (Canvas)formatter.Deserialize(fs);

with this:

public class CanvasSurrogate : ISerializationSurrogate
{
    public void GetObjectData(object obj, SerializationInfo info, StreamingContext context)
    {
        Canvas c = (Canvas)obj;
        info.AddValue("Name", c.Name);
    }
    public object SetObjectData(object obj, SerializationInfo info, StreamingContext context, ISurrogateSelector selector)
    {
        Canvas c = (Canvas)obj;
        c.Name = info.GetString("Name");  //Errors here on the assignment
        return obj;
    }
}

Update:
Hmmmm. Maybe this is WPF related - 'Name' is a DependencyProperty......