By default, no, you cannot serialize readonly properties to XML .

But what do you really want to do?  What's the end goal?  There may be a way
to accomplish what you want.

If you serialize with the BinaryFormatter, you can get all obj properties.
http://msdn.microsoft.com/library/en-us/cpref/html/frlrfSystemRuntimeSerializati
onFormattersBinaryBinaryFormatterClassTopic.asp

Alternatively, staying with the XmlSerializer, you could use a hack where
you provide a public setter method, which does nothing.  In this case the
XML Serialization will work, but de-serialization may not behave the way you
want.

public class MyClass {
 private int _myInt;
 public int MyInt {
    get { return _myInt; }
    set { }  // do nothing!!
 }
}

But understand that in this case, at De-serialize time, your data will
disappear.  The XmlSerializer.Deserialize() method will call your setter,
which will do nothing (by your design) and then the data from the XML file
will NOT be set in the (deserialized) object instance.

Also you will have confusing code that may be hard to use or hard to
maintain later: Users of your class may invoke the setter expecting it to
actually work.

-Dino