Question

I have a class which is serialized to XML. This class has an Object member variable. How can I properly serialize this item? Obviously, it should be written as a string, but when read, it should become any type.

public class MyClass
{
    public MyClass()
        : this("", null)
    {
    }

    public MyClass(String name, Object value)
    {
        Name = name;
        Value = value;
    }

    [XmlAttribute("name")]
    public String Name;

    [XmlAttribute("value")] // Won't work!
    public Object Value;
}

Edit: Interestingly, [XmlElement()] is able to serialize the Object type. Thus, one workaround is to use a value instead of an attribute.

Answer 1

You can’t serialize an Object as attribute – that would mean you’d have to serialize a (possibly) complex object into a string.

As XmlAttributeAttribute docs state:

You can assign the XmlAttributeAttribute only to public fields or public properties that return a value (or array of values) that can be mapped to one of the XML Schema definition language (XSD) simple types (including all built-in datatypes derived from the XSD anySimpleType type). The possible types include any that can be mapped to the XSD simple types, including Guid, Char, and enumerations. See the DataType property for a list of XSD types and how they are mapped to.NET data types.