.net class xml attribute to create multiple namespaces

Question

I want to have a class property when serializing it to have multiple namespaces in the output. The XmlElementAttribute isn't working for me. Can anyone help?

My code:

XML Output:

<MyClass>
    <Property1 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"/>
    <Property2/>
</MyClass>

Class:

public class MyClass
{
    [XmlElementAttribute(Namespace = "http://www.w3.org/2001/XMLSchema-instance")]
    public string Property1 { get; set; }

    public string Property1 { get; set; }
}

Answer 1

The serializer can defines prefixes (like in your example) but you only have one namespace per element. Use XmlElementAttribute (aka XmlElement) for the single relevant namespace and define prefixes when you serialize.

To get this:

<?xml version="1.0" encoding="utf-16"?>
<OrderedItem xmlns:inventory="http://www.cpandl.com" xmlns:money="http://www.cohowinery.com">
    <inventory:ItemName>Widget</inventory:ItemName>
    <inventory:Description>Regular Widget</inventory:Description>
    <money:UnitPrice>2.3</money:UnitPrice>
    <inventory:Quantity>10</inventory:Quantity>
    <money:LineTotal>23</money:LineTotal>
</OrderedItem>

You have:

public class OrderedItem
{
    [XmlElementAttribute(Namespace = "http://www.cpandl.com")]
    public string ItemName { get; set; }
    [XmlElementAttribute(Namespace = "http://www.cpandl.com")]
    public string Description { get; set; }
    [XmlElementAttribute(Namespace = "http://www.cohowinery.com")]
    public decimal UnitPrice { get; set; }
    [XmlElementAttribute(Namespace = "http://www.cpandl.com")]
    public int Quantity { get; set; }
    [XmlElementAttribute(Namespace = "http://www.cohowinery.com")]
    public int LineTotal { get; set; }
}

And serialize with prefixes set in your XmlSerializerNamespaces:

OrderedItem example = new OrderedItem
            {
                ItemName = "Widget",
                Description = "Regular Widget",
                UnitPrice = (decimal) 2.3,
                Quantity = 10,
                LineTotal = 23
            };

XmlSerializer serializerX = new XmlSerializer(example.GetType());
XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
namespaces.Add("inventory", "http://www.cpandl.com");
namespaces.Add("money", "http://www.cohowinery.com");
serializerX.Serialize(Console.Out, example, namespaces);