Question

I’m deserializing some XML from an old application into an object in my current application. The old XML often has empty elements (<SomeElement />) which are currently deserialized as empty strings ("").

I agree that this is the most appropriate behaviour, but it is a minor irritant; I’d rather they were deserialized as Nothing or ideally ignored – the effect would be the same.

Is there a means of ignoring these elements? Or can I have them deserialized as Nothing?

CONCLUSION:
Both solutions listed have their merits…

Aaron’s solution would be ideal if I had just had one problem property – it’s a single fix, for a single problem.

Where there are multiple properties that are problematic, svick’s solution is preferred. Implementing ISerializable involves creating a constructor and a GetObjectData method with specific handling for each property.

My decision: since my problem only involves some legacy XML files (which will die out over time), and since String.IsNullOrEmpty enables me to ignore the problem, I’ve decided to do nothing. I don’t want the additional overhead of maintaining the ISerializable interface if not necessary – but in many cases, this would be good solution, so it’s my selected answer.

Answer 1

I didn’t find any other clear simple way to do this. But you can always implement IXmlSerializable and handle the serialization and deserialization by yourself:

Public Sub ReadXml(ByVal reader As XmlReader) Implements IXmlSerializable.ReadXml

    reader.ReadStartElement()
    If (reader.Name = "SomeElement") Then
        Dim someElementValue = reader.ReadElementString()

        If someElementValue <> String.Empty Then
            SomeElement = someElementValue
        End If
    End If
    reader.ReadEndElement()

End Sub