以特定顺序编写 XML 属性和命名空间声明

Question

I am trying to make an XML file with a root element:

<urn:Command complete="true" xmlns:urn="namespaceURI">

So I have an element Command a namespace namespaceURI a prefix urn and finally an attribute string with name complete a value true and no namespace.

The code I have made to do this returns:

<urn:Command xmlns:urn="namespaceURI" complete="true">

So the problem is I would like the attribute string to be before the namespace definition in the XML file and I can't find a similar problem on this website.

I have tried writing a StartElement with a prefix and namespace then writing an AttributeString with no namespace, this returns the root element with the defined namespace first followed by the attribute string. I have also tried only defining a start element and then two attribute strings but then I can't find a way to write the prefix to the start element.

This is my original code that returns the root element with a namespace definition first the the attribute definition:

`Dim Writer as System.Xml.XmlWriter;
dim writerSettings  as System.Xml.XmlWriterSettings;
dim basePath as string;
dim source as string;
dim destination as string;

writerSettings = new System.Xml.XmlWriterSettings();
'writerSettings.ConformanceLevel= false;
'writerSettings.Encoding = new System.Text.UTF8Encoding(false);
writerSettings.OmitXmlDeclaration = false;

basePath = System.IO.Path.Combine("\\wnlcuieb502\WEI\Outbound","RolexSet");
source  = System.IO.Path.Combine(basePath,"\\wnlcuieb502\WEI\Outbound","TEST.XML");

Writer = System.Xml.XmlWriter.Create(source,writerSettings);
Writer.WriteStartDocument();

Writer.WriteStartElement("urn","SetPackagingOrder","urn:laetus.com:ws:tts:mes");
Writer.WriteAttributeString("complete",null,"true");
Writer.WriteEndElement();
Writer.WriteEndDocument();
Writer.dispose();


try
    destination = System.IO.Path.Combine(basePath,"TEST.XML");
    while not System.IO.File.Exists(destination)        
        System.IO.File.Move(source,destination);
    endwhile;
catch
    LogError(Me.HierarchicalName + ": Could not move XML file: "+ "TEST.XML" +" from " + source + " to " + destination + ", Error: " + error.Message);
endtry;`

Answer 1

XML attribute and namespace declaration order should never matter

Attribute order is insignificant per the XML Recommendation :

Note that the order of attribute specifications in a start-tag or empty-element tag is not significant.

Namespace declaration are like attributes ( W3C Namespaces in XML Recommendation , section 3 Declaring Namespaces ),

[Definition: A namespace (or more precisely, a namespace binding) is declared using a family of reserved attributes. Such an attribute's name must either be xmlns or begin xmlns: . These attributes, like any other XML attributes, may be provided directly or by default . ]

with similarly insignificant ordering.

So, no conformant XML tool or library will care about the order of XML attributes and XML namespace declarations, and neither should you.

This is why XML libraries generally do not provide a way to constrain attribute ordering, and trying to do so is almost always a sign that you're doing something wrong.

---

...except for rarely needed normalization applications

The XML recommendations will all consider attribute ordering and namespace declaration ordering to be insignificant, but see the section on attribute processing in the XML Normalization Recommendation or the Canonical XML Recommendation if your application has an unavoidable need for attribute ordering. The need to establish lexical equality/inequality for digital signatures ( XML Signature Syntax and Processing Version 1.1 ) is one such exception.

See also (but only if you absolutely must order XML attributes and namespaces declarations):

• .NET

  • Controlling the order of XML namepaces
  • How to specify the order of XmlAttributes, using XmlSerializer
  • .NET Serialization Ordering

• Java

  • Order of XML attributes after DOM processing
  • Java XML library that preserves attribute order

• XSLT

  • XSLT to order attributes

• Multi-platform

  • Saxon serialization parameters : saxon:attribute-order? and saxon:canonical?