C# XmlSerializer xmlns in child element matching parent

Question

I'm using XmlSerializer to create a xml doc in use for ebay's large merchant services.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<BulkDataExchangeRequests xmlns="urn:ebay:apis:eBLBaseComponents">
    <Header>
        <SiteID>0</SiteID>
        <Version>775</Version>
    </Header>
    <AddFixedPriceItemRequest xmlns="urn:ebay:apis:eBLBaseComponents">
<Version>775</Version>

<Item>
    <AutoPay>false</AutoPay>
    <BuyerProtection>ItemIneligible</BuyerProtection>
    <BuyItNowPrice currencyID="USD">0.0</BuyItNowPrice>
    <Country>US</Country>
    <Currency>USD</Currency>
    <Description>test</Description>
    <GiftIcon>0</GiftIcon>
</Item>
</AddFixedPriceItemRequest>
</BulkDataExchangeRequests>

The problem I'm having is getting the AddFixedPriceItemRequest generated by the serializer to actually contain that xmlns like the BulkDataExchangeRequests element has. It seems to be a requirement in order for this to work. I generate the bulk tag using:

writer.WriteStartElement("BulkDataExchangeRequests", "urn:ebay:apis:eBLBaseComponents");

I create a serializer.

serializer = new XmlSerializer(typeof(AddFixedPriceItemRequestType));//, "urn:ebay:apis:eBLBaseComponents");

and serialize with the namespace

request = new AddFixedPriceItemRequestType()
{
//populate data.
};

XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
namespaces.Add("", "urn:ebay:apis:eBLBaseComponents");

serializer.Serialize(writer, request, namespaces);

This is the type with the xml attributes:

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Xml", "2.0.50727.5420")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace="urn:ebay:apis:eBLBaseComponents",TypeName="AddFixedPriceItemRequest")]
public partial class AddFixedPriceItemRequestType : AbstractRequestType {
//filled in class
}

my output ends up like this:

<AddFixedPriceItemRequest xmlns="">
   <ErrorLanguage xmlns="urn:ebay:apis:eBLBaseComponents">en_US</ErrorLanguage>
    <Version xmlns="urn:ebay:apis:eBLBaseComponents">837</Version>
    <Item p4:type="Item" xmlns:p4="http://www.w3.org/2001/XMLSchema-instance" xmlns="urn:ebay:apis:eBLBaseComponents">

Could someone help out with how to get xmlns of addfixedpriceitemrequest set to match the bulk xmlns via the serializer. Or recommend another way to do it. I was trying to avoid writing each property out with createelement/writeelement.

Answer 1

The problem most likely lies in the XmlTypeAttribute - it seems you use your class as the top level container - you should use XmlRootAttribute insted. This way you will get urn:ebay:apis:eBLBaseComponents placed in correct location.

Sample:

void Main()
{
    var t = new A {FieldOfB = new B {C = 5}};

    var serializer = new XmlSerializer(typeof(A));


    using (var writer = new StringWriter())
    {
        serializer.Serialize(writer, t);
        writer.ToString().Dump();
    }
}

When used with this class definitions:

[System.Xml.Serialization.XmlTypeAttribute(Namespace="urn:ebay:apis:eBLBaseComponents")]
public class A
{
    public B FieldOfB {get;set;}
}

public class B
{
    public int C {get;set;}
}

yields this result:

<?xml version="1.0" encoding="utf-16"?>
<A xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <FieldOfB xmlns="urn:ebay:apis:eBLBaseComponents">
    <C>5</C>
  </FieldOfB>
</A>

And if you fix the attribute:

[System.Xml.Serialization.XmlRootAttribute(Namespace="urn:ebay:apis:eBLBaseComponents")]
public class A
{
    public B FieldOfB {get;set;}
}

public class B
{
    public int C {get;set;}
}

You get this:

<?xml version="1.0" encoding="utf-16"?>
<A xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="urn:ebay:apis:eBLBaseComponents">
  <FieldOfB>
    <C>5</C>
  </FieldOfB>
</A>

Answer 2

That works for me

---

 ItemType itemType = new ItemType()
 {
     //populate data.
 };
 ApiCall apiCall = new AddItemCall() { Item = itemType };
 AddItemRequestType addFixedPriceItemRequestType = ((AddItemCall)apiCall).ApiRequest;
 XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces(new XmlQualifiedName[] {
     new XmlQualifiedName(string.Empty, "urn:ebay:apis:eBLBaseComponents")});
 XmlSerializer xmlSerializer = new XmlSerializer(
     addFixedPriceItemRequestType.GetType(), "urn:ebay:apis:eBLBaseComponents");
 MemoryStream memoryStream = new MemoryStream();
 xmlSerializer.Serialize(memoryStream, addFixedPriceItemRequestType , namespaces);
 memoryStream.Seek((long)0, SeekOrigin.Begin);
 XmlDocument xmlDocument = new XmlDocument();
 xmlDocument.Load(memoryStream);
 memoryStream.Close();
 string addItemRequestTypeXML = xmlDocument.OuterXml;

---

The output is going to be:

---

 <AddItemRequestType xmlns="urn:ebay:apis:eBLBaseComponents">
  <Item>
    <ApplicationData></ApplicationData>
    <AutoPay>false</AutoPay>
    <CategoryMappingAllowed>true</CategoryMappingAllowed>
    <Country>US</Country>
    <Currency>EUR</Currency>
    <Description>
    ....

 <AddItemRequestType>

Answer 3

eBay requires namespace setting in Trade API only. One solution is to remove namespace setting in BulkDataExchange objects, and add namespace setting in Trade API object only. This is not a standard XML format, however eBay only accept this.

In your case, this might do the trick to eBay:

writer.WriteStartElement("BulkDataExchangeRequests", "");