Thank you, Alex! I've been trying to make it work, but there's a twist
in my situation which I haven't added yet:

My UserControl-derived class is called Basic, and I have some classes
derived from Basic. I never directly use Basic, only its child
classes. I need to serialize a List<Basic>, filled with objects of the
child classes, but I don't know in advance what kind of objects are
used. I found examples how this should be done (a simple example, no
IXmlSerializable interface involved). So when I serialize/deserialize,
I use the following constructor for XmlSerializer class:

public XmlSerializer(Type type, Type[] extraTypes);
like this:
XmlSerializer ser = new XmlSerializer(typeof(List<Basic>), new Type[]
{ typeof(BasicChild1), ..., typeof(BasicChildN) } );

In the simple example, I see that there is an xsi:type="ChildClass"
attribute generated by the serializer. I guess serializer uses this
attribute to construct the object of the appropiate type when
deserializing.

Now the problem: How can I make this work with IXmlSerializable's
ReadXml?
I can generate the appropiate attribute in WriteXml with
XmlWriter.WriteAttributeString, but ReadXml should do something with
this attribute, right?

Thank you again for anyone helping me!
Chris

Alex Meleta ?rta: