Deserialize empty XML element (VB.NET)

[mcollier]

I'm having some trouble figuring out how to deserialize an empty XML
element in VB.NET. Let's say I'm trying to deserialize XML such as:
<Order>
<OrderRefNumber/>
<Customer>Bob</Customer>
</Order>

I would then have a simple entity object to represent the XML data.
That object would have a property such as:

'---------------- begin code -----------
<System.Xml.Serialization.XmlElementAttribute(Form :=System.Xml.Schema.XmlSchemaForm.Unqualified)>
_
Public Property OrderRefNumber() As Long
Get
Return Me.refNumber
End Get
Set(ByVal Value As Long)
Me.refNumber = Value
End Set
End Property

<XmlIgnore()> _
Public Property OrderRefNumberSpecified() As Boolean
Get
Return Not Me.refNumber = 0
End Get
Set(ByVal Value As Boolean)
If Not Value Then
Me.refNumber = 0
End If
End Set
End Property
'--------------- end code ----------

Where Me.refNumber is a private long field.

Whenever I try to deserialize the XML, I get the following exception
message:
System.InvalidOperationException: There is an error in XML document
(23, 23). ---> System.FormatException: Input string was not in a
correct format.
at System.Number.ParseInt64(String s, NumberStyles style,
NumberFormatInfo info)
at System.Xml.XmlConvert.ToInt64(String s)
........

I'm pretty sure that the XmlSerializer is having trouble deserializing
the empty OrderRefNumber element. How do I fix this?
Thanks!

[mcollier]

Nevermind.