send null values during serialisation - vb.net

Question

Trying to determine best way to seralize so I can send in a null value for middle name if not entered
My xml:
<Contact>
<ID />
<First_Name />
<Middle_Name xmlns:xsi="w3.org/2001/XMLSchema-instance" xsi:nil="true" />
<Last_Name />
<TelephoneNumbers>
<TelephoneNumber>
<Number />
<IsHome />
<IsWork />
<IsCell />
<ReachableAfterHrs />
</TelephoneNumber>
</TelephoneNumbers>
</Contact>
The vb class created for serialization/deserialisation
'''<remarks/>
<System.Xml.Serialization.XmlTypeAttribute(AnonymousType:=True), _
System.Xml.Serialization.XmlRootAttribute([Namespace]:="", IsNullable:=False)> _
Partial Public Class Contact
Private idField As String
Private first_NameField As String
Private middle_NameField As ContactMiddle_Name
Private last_NameField As String
Private telephoneNumbersField As ContactTelephoneNumbers
'''<remarks/>
Public Property ID() As String
Get
Return Me.idField
End Get
Set(value As String)
Me.idField = Value
End Set
End Property
'''<remarks/>
Public Property First_Name() As String
Get
Return Me.first_NameField
End Get
Set(value As String)
Me.first_NameField = Value
End Set
End Property
'''<remarks/>
Public Property Middle_Name() As ContactMiddle_Name
Get
Return Me.middle_NameField
End Get
Set(value As ContactMiddle_Name)
Me.middle_NameField = Value
End Set
End Property
'''<remarks/>
Public Property Last_Name() As String
Get
Return Me.last_NameField
End Get
Set(value As String)
Me.last_NameField = Value
End Set
End Property
'''<remarks/>
Public Property TelephoneNumbers() As ContactTelephoneNumbers
Get
Return Me.telephoneNumbersField
End Get
Set(value As ContactTelephoneNumbers)
Me.telephoneNumbersField = Value
End Set
End Property
End Class
'''<remarks/>
<System.Xml.Serialization.XmlTypeAttribute(AnonymousType:=True)> _
Partial Public Class ContactMiddle_Name
Private nilField As Boolean
'''<remarks/>
<System.Xml.Serialization.XmlAttributeAttribute(Form:=System.Xml.Schema.XmlSchemaForm.Qualified, [Namespace]:="w3.org/2001/XMLSchema-instance")> _
Public Property nil() As Boolean
Get
Return Me.nilField
End Get
Set(value As Boolean)
Me.nilField = Value
End Set
End Property
End Class
'''<remarks/>
<System.Xml.Serialization.XmlTypeAttribute(AnonymousType:=True)> _
Partial Public Class ContactTelephoneNumbers
Private telephoneNumberField As ContactTelephoneNumbersTelephoneNumber
'''<remarks/>
Public Property TelephoneNumber() As ContactTelephoneNumbersTelephoneNumber
Get
Return Me.telephoneNumberField
End Get
Set(value As ContactTelephoneNumbersTelephoneNumber)
Me.telephoneNumberField = Value
End Set
End Property
End Class
'''<remarks/>
<System.Xml.Serialization.XmlTypeAttribute(AnonymousType:=True)> _
Partial Public Class ContactTelephoneNumbersTelephoneNumber
Private numberField As Object
Private isHomeField As Object
'''<remarks/>
Public Property Number() As Object
Get
Return Me.numberField
End Get
Set(value As Object)
Me.numberField = Value
End Set
End Property
'''<remarks/>
Public Property IsHome() As Object
Get
Return Me.isHomeField
End Get
Set(value As Object)
Me.isHomeField = Value
End Set
End Property
End Class
Upon deserialising, the output contains tag which represents an empty element rather then a null. The client wants us to send null rather then empty.

Answer 1

Try giving the properties the following attribute <XmlElement(IsNullable := True)>.
http://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlelementattribute.isnullable(v=vs.110).aspx