Question

Let’s say we have a class Root that contains an array of an abstract class BaseClass that is implemented by 2 derived classes Derived1 and Derived2

[XmlRootAttribute("root")]
public class Root
{
  [XmlElement("derived1", typeof(Derived1))]
//[XmlElement("derived2", typeof(Derived2))]
  public BaseClass[];
}

public abstract class BaseClass { }

public class Derived1 : BaseClass { }

public class Derived2 : BaseClass { }

How can i tell the XmlSerializer that instances of Derived2 should be ignored during serialization?

Thanks in advance!

Answer 1

I was wrong, there is: ShouldSerialize does the magic MSDN
Assuming your property is “Obj”

public bool ShouldSerializeObj() {
      return Obj is Derived1;
   }

Edit:
If you want to take care of the serialization, you can implement IXmlSerializable interface as you said like this

public class Derived1 : BaseClass, IXmlSerializable 
{ 
  public XmlSchema GetSchema() { return null; }

  public void ReadXml(System.Xml.XmlReader reader)
  {
    reader.MoveToContent();
    Name = reader.GetAttribute("Name");
    reader.ReadStartElement();
    if (!reader.IsEmptyElement)
    {
      YourProperty = reader.ReadElementString("YourElem");
      reader.ReadEndElement();
    }
  }

  public void WriteXml(System.Xml.XmlWriter writer)
  {
    witer.WriteAttributeString("Name", Name);
    writer.WriteElementString("YourElem", "ThisIsMyContent");
  }
}

This way you can take care of the serialization.
Note: The GetSchema() is supposed to return null