How to specify multiple namespaces in DataContract attribute

Question

Given a business object 'Order', how can I implement a DataContract attribute so that the Order object serializes to this:

<Order xmlns="http://schemas.datacontract.org/2004/07/appulsive.MyCompany.SomeWebService"
xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
...etc.
</Order>

There appears to be a default namespace as well as a specific one. I have been told this is a requirement to work with the web service in question.

TIA.

Answer 1

Assuming you are using DataContractSerializer , you just need to add [DataContract(Name="desired name", Namespace="desired namespace")] to the class:

[DataContract(Name = "Order", Namespace = "http://schemas.datacontract.org/2004/07/appulsive.MyCompany.SomeWebService")]
public class Order
{
    /// Various data members
    [DataMember]
    public string SomeStuff { get; set; }
}

Having done so, you also need to mark all properties you wish to serialize with [DataMember] since data contract serialization is opt-in. Then the XML generated by DataContractSerializer will look like:

 <Order xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/appulsive.MyCompany.SomeWebService"> <SomeStuff>some stuff</SomeStuff> </Order> 

As you can see, the namespace "http://www.w3.org/2001/XMLSchema-instance" is automatically included. That's because it is a standard namespace that contains definitions for standard attributes including nil (representing a null value) and type (holding type information for a polymorphic type). Since these attributes are almost always required, it's conventional to add the namespace to the root element, and in fact DataContractSerializer does so.