As a followup to this point, I have discovered how the get Namespace 
Prefixes add......
When serializing a class using an XmlSerializer, one of the parameters that 
can be passed in is an object containing namespaces.  This is what will 
modify the XML output to use the appropriate Namespace prefixes.

SerializableObjectFoo oSerializableObjectFoo;
XmlSerializer xsSerializer;
TextWriter twWriter;
XmlSerializerNamespacew xsnNamespaces;

oSerializableObjectFoo = new SerializableObjectFoo():
oSerializableObjectFoo.ElementName.Value1 = "A";
oSerializableObjectFoo.ElementName.Value2 = "B";

xsnNamespaces = new XmlSerializerNamespaces();
xsnNamespaces.Add("", "http://www.w3.org/schemas");
xsnNamespaces.Add("rex", "http://www.rex.org/schemas");
xsnNamespaces.Add("xsi", "http://www.w3.org/2001/XMLSchema-instance");

twWriter = new StreamWriter(@"C:\Temp\Export.xml");
xsSerializer.Serialize(twWriter, oSerializableObjectFoo, xsnNamespaces);
twWriter.Close();

***********************
Then the class will look something like
***********************
[Serializable]
 [XmlElementAttribute(ElementName="Foo", IsNullable=true,
 Form=XmlSchemaForm.Qualified)]
 public class Foo
 {
    [XmlElementAttribute(ElementName="ElementName", 
Namespace="http://www.rex.org/schemas")]
    public ElementName ElementName
    {
        get {return menElementName;}
        set {menElementName = value;}
    }
 }

[XmlRoot(ElementName="ElementName", Namespace = 
"http://www.rex.org/schemas")]
[XmlType(TypeName="elementNameType", Namespace = 
"http://www.rex.org/schemas")]
 public class ElementName
{
    [XmlElement("Value1")]
    public string Value1
    {
        get;
        set;
     }
    [XmlElement("Value2")]
    public string Value2
    {
        get;
        set;
     }
 }

If you only declare the XmlRoot Attribute on the ElementName class, then 
only the children will get the Namespace prefix.  The ElementName property 
in the Foo Class needs to namespace also so it is explicitly declared.  Make 
sure the Namespace= "<Value>" matches exactly as what is put in the 
XmlSerializableNamespaces collection otherwise the Serializer won't 
recognize the item and prefix the Element with the Namespace prefix.


"Techno_Dex" <nospamchurst@o...> wrote in message 
news:%23PEIX5d$GHA.2256@T......
> Can anyone tell me how to add an XMLNamespace prefix to a C# class 
> declaration?  I have a couple of different namespaces that must be 
> declared in my XML file but I can't figure out what class/property 
> attributes I need to add to have a namespace prefix generated in front of 
> the element when the class is serialized.
>
> I am looking for "rex" so the serialization will occur like the following.
> <rex:ElementName>
>  <rex:Value1> A</rex:Value1>
>  <rex:Value2> B</rex:Value2>
> </rex:ElementName>
>
> So far all I am able to come up with is
> <ElementName xmlns="rex">
>  <Value1 xmlns="rex"> A</Value1>
>  <Value2 xmlns="rex"> B</Value2>
> </rex:ElementName >
>
> I get this when I have the following
> [XmlElementAttribute(ElementName="Foo", IsNullable=true, 
> Form=XmlSchemaForm.Qualified)]
> public class Foo
> {
>    [XmlElement("ElementName")]
>    public ElementName ElementName
>    {
>        get {return menElementName;}
>        set {menElementName = value;}
>    }
> }
>
> public class ElementName
> {
>    [XmlElement("Value1")]
>    public string Value1
>    {
>        get;
>        set;
>     }
>    [XmlElement("Value2")]
>    public string Value2
>    {
>        get;
>        set;
>     }
> }
>