XmlElement.Attributes is dropping namespaces

Question

Hi all;

If you prefer as a fiddle - click here.

In my debugger, I have an XmlElement.OuterXml of:

<?xml version="1.0"?>
<p:sld mc:Ignorable="p14 a14 p15 p16 a16 thm15 adec ahyp v"
  xmlns:v="urn:schemas-microsoft-com:vml"
  xmlns:asvg="http://schemas.microsoft.com/office/drawing/2016/SVG/main"
  xmlns:ahyp="http://schemas.microsoft.com/office/drawing/2018/hyperlinkcolor"
  xmlns:adec="http://schemas.microsoft.com/office/drawing/2017/decorative"
  xmlns:thm15="http://schemas.microsoft.com/office/thememl/2012/main"
  xmlns:p16="http://schemas.microsoft.com/office/powerpoint/2015/main"
  xmlns:p15="http://schemas.microsoft.com/office/powerpoint/2012/main"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:a16="http://schemas.microsoft.com/office/drawing/2014/main" 

Note it's mc:Ignorable, not Ignorable.

I call XmlElement.Attributes and one of the attributes is for Ignorable but... 

It's lost the prefix/namespace.

Any idea what is going on here?

ps- Also posted on StackOverflow, but the response there is it seems to be a bug.

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Answer 1

Try an alternative to inner.SetAttribute:

System.Xml.XmlDocument doc = new System.Xml.XmlDocument( );
var root = doc.CreateElement( "root" );
doc.AppendChild( root );

const string ns = "http://schemas.openxmlformats.org/markup-compatibility/2006";

root.SetAttribute( "xmlns:mc", ns );

var inner = doc.CreateElement( "inner" );
root.AppendChild( inner );

var ignorable = doc.CreateAttribute( "mc", "Ignorable", ns );
ignorable.Value = "p14 a14 p15 p16 a16 thm15 adec ahyp v";
inner.Attributes.Append( ignorable );

Console.WriteLine( doc.OuterXml );

var list = inner.Attributes;
foreach( System.Xml.XmlAttribute attr in list )
	Console.WriteLine( attr.Name );

The first SetAttribute can be replaced too.

Answer 2

Hi;

Thanks for the suggestion. Unfortunately, it would be a royal PITA to pass the XmlDocument down to the several hundred places we do this. Is there any way to get this working without the document?

thanks - dave

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What we did for the last 6 months - Made the world's coolest reporting & docgen system even more amazing

Answer 3

Hi DavidThi808,

Thanks for your feedback.

I find that both solutions under this thread and in StackOverflow can successfully get the prefix of 'Ignorable' attribute.

>>it would be a royal PITA to pass the XmlDocument down to the several hundred places we do this. Is there any way to get this working without the document?

Could you provide more detailed descriptions about this? It will help us analyze your problem.

We are waiting for your update.

Best Regards,

Xingyu Zhao

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Answer 4

Hi Xingyu;

I've found a way to do this, without have to pass the XmlDocument down.

However, I think this is a bug. Can you please report it to the .Net team?

thanks - dave

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What we did for the last 6 months - Made the world's coolest reporting & docgen system even more amazing

Answer 5

[EDIT: removed as I see where the problem is]

I modified your example a bit to get the problem you said:

using System;

public class Program
{
	public static void Main()
	{
		System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
		var root = doc.CreateElement("root");
		root.SetAttribute("xmlns:mc", "http://schemas.openxmlformats.org/markup-compatibility/2006");
		doc.AppendChild(root);
		
		System.Xml.XmlDeclaration xml_declaration;
        xml_declaration = doc.CreateXmlDeclaration("1.0", "utf-8", "yes");

        System.Xml.XmlElement document_element = doc.DocumentElement;
        doc.InsertBefore(xml_declaration, document_element);

		var inner = doc.CreateElement("inner");
		root.AppendChild(inner);
		inner.SetAttribute("Ignorable", "http://schemas.openxmlformats.org/markup-compatibility/2006", "p14 a14 p15 p16 a16 thm15 adec ahyp v");

		var list = inner.Attributes;
		foreach (System.Xml.XmlAttribute attr in list)
			Console.WriteLine(attr.Name);
		
		Console.WriteLine(doc.OuterXml);
	}
}

In doc.OuterXml content, you can see the attribute is properly named "mc:Ignorable", yet attr.Name does not show it correctly.

EDIT2: Now I get it to work as expected:

using System;

public class Program
{
	public static void Main()
	{
		const string ns = "http://schemas.openxmlformats.org/markup-compatibility/2006";
		System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
		var root = doc.CreateElement("root");
		root.SetAttribute("xmlns:mc", ns);
		doc.AppendChild(root);
		
		System.Xml.XmlDeclaration xml_declaration;
        xml_declaration = doc.CreateXmlDeclaration("1.0", "utf-8", "yes");

        System.Xml.XmlElement document_element = doc.DocumentElement;
        doc.InsertBefore(xml_declaration, document_element);

		var inner = doc.CreateElement("inner");

		var ignorable = doc.CreateAttribute( "mc", "Ignorable", ns );
		ignorable.Value = "p14 a14 p15 p16 a16 thm15 adec ahyp v";
		inner.Attributes.Append( ignorable );
		
		root.AppendChild(inner);
		
		var list = inner.Attributes;
		foreach (System.Xml.XmlAttribute attr in list)
			Console.WriteLine(attr.Name);
	
		Console.WriteLine(doc.OuterXml);
	}
}