The XmlSerializerNamespaces contains a collection of XML namespaces, each with an associated prefix. The XmlSerializer uses an instance of the XmlSerializerNamespaces class to create qualified names in an XML document.

XML namespaces contained by the XmlSerializerNamespaces must conform to the www.w3.org specification named Namespaces in XML.

XML namespaces provide a way to qualify the names of XML elements and attributes in XML documents. A qualified name consists of a prefix and a local name, separated by a colon. The prefix functions only as a placeholder; it is mapped to a URI that specifies a namespace. The combination of the universally-managed URI namespace and the local name produces a name that is guaranteed to be universally unique.

To create qualified names in an XML document:

1. Create an XmlSerializerNamespaces instance.

2. Add each prefix and namespace pair that you want to the instance.

3. Apply the appropriate.NET attribute to each property or class that the XmlSerializer serializes into an XML document. The available attributes are:

• XmlArrayAttribute

• XmlArrayItemAttribute

• XmlAttributeAttribute

• XmlElementAttribute

• XmlRootAttribute

• XmlTypeAttribute

1. Set the Namespace property of each attribute to one of the namespace values from the XmlSerializerNamespaces object.

2. Pass the XmlSerializerNamespaces to the Serialize method of the XmlSerializer.

Note
The creation of an empty namespace and prefix pair is not supported. That is, you cannot create a pair using the following code:

Dim ns As XmlSerializerNamespaces ns = New XmlSerializerNamespaces()
ns.Add("", "")

The following example creates an XmlSerializerNamespaces object, and adds two prefix and namespace pairs to it. The example then passes the XmlSerializerNamespaces to the Serialize method, which serializes a Books object into an XML document. Using the XmlSerializerNamespaces object, the Serialize method qualifies each XML element and attribute with one of the two namespaces.

Imports System
Imports System.IO
Imports System.Xml
Imports System.Xml.Serialization


Public Class Run

    Public Shared Sub Main()
        Dim test As New Run()
        test.SerializeObject("XmlNamespaces.xml")
    End Sub    

    Public Sub SerializeObject(ByVal filename As String)
        Dim s As New XmlSerializer(GetType(Books))
        ' Writing a file requires a TextWriter.
        Dim t As New StreamWriter(filename)

        ' Create an XmlSerializerNamespaces object and add two
        ' prefix-namespace pairs. 
        Dim ns As New XmlSerializerNamespaces()
        ns.Add("books", "http://www.cpandl.com")
        ns.Add("money", "http://www.cohowinery.com")

        ' Create a Book instance.
        Dim b As New Book()
        b.TITLE = "A Book Title"
        Dim p As New Price()
        p.price = CDec(9.95)
        p.currency = "US Dollar"
        b.PRICE = p
        Dim bks As New Books()
        bks.Book = b
        s.Serialize(t, bks, ns)
        t.Close()
    End Sub
End Class

Public Class Books
    <XmlElement(Namespace := "http://www.cohowinery.com")> _
    Public Book As Book
End Class

<XmlType(Namespace := "http://www.cpandl.com")> _
Public Class Book
    <XmlElement(Namespace := "http://www.cpandl.com")> _
    Public TITLE As String

    <XmlElement(Namespace := "http://www.cohowinery.com")> _
    Public PRICE As Price
End Class

Public Class Price
    <XmlAttribute(Namespace := "http://www.cpandl.com")> _
    Public currency As String

    <XmlElement(Namespace := "http://www.cohowinery.com")> _
    Public price As Decimal
End Class

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role not supported), Windows Server 2003 SP2

.NET Framework

.NET Framework Client Profile

Reference

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