Develop Reference

Correct way to add a namespace to an element using XmlDocument

I have to modify a incoming SOAP XML message to add a namespace to one of the elements so that the deserialisation will work. However when I add the xmlns attribute to the correct element, I get an error when I try to load the xml in to an XmlWriter via a stream (which I need to do to in my IClientMessageInspector implementation to replace the Message reply).
The prefix '' cannot be redefined from '' to 'http://www.example.com' within the same start element tag.
I have a work around, which is that after I've modifed the attribute, I reload the entire XML document from it's own OuterXML. This works for some reason, but makes me think there must be a 'correct' way to do this.
Here's a sample test that demonstrates the problem and my current solutions:
[Test]
public void XmlNamespaceTest()
{
var originalXmlString = "<?xml version=\"1.0\" encoding=\"utf-8\"?><TestElement><Child>thing</Child></TestElement>";
var desiredXmlString = "<?xml version=\"1.0\" encoding=\"utf-8\"?><TestElement xmlns=\"http://www.example.com\"><Child>thing</Child></TestElement>";
var doc = new XmlDocument();
doc.LoadXml(originalXmlString);
Assert.That(originalXmlString, Is.EqualTo(doc.OuterXml));
// Write this document via an XMLWriter
var ms = new MemoryStream();
var xmlWriter = XmlWriter.Create(ms);
doc.WriteTo(xmlWriter);
xmlWriter.Flush();
ms.Position = 0;
StreamReader sr = new StreamReader(ms);
var originalXmlViaXmlWriter = sr.ReadToEnd();
Assert.That(originalXmlString, Is.EqualTo(originalXmlViaXmlWriter));
// Add the namespace to the element
((XmlElement)doc.GetElementsByTagName("TestElement").Item(0))?.SetAttribute("xmlns", "http://www.example.com");
Assert.That(desiredXmlString, Is.EqualTo(doc.OuterXml));
// Now attempt to write this modified xml via an XMLWriter
ms.SetLength(0);
xmlWriter = XmlWriter.Create(ms);
//Uncomment line below to fix the error.
//doc.LoadXml(doc.OuterXml);
doc.WriteTo(xmlWriter);
xmlWriter.Flush();
ms.Position = 0;
sr = new StreamReader(ms);
var modifedXmlViaXmlWriter = sr.ReadToEnd();
Assert.That(desiredXmlString, Is.EqualTo(modifedXmlViaXmlWriter));
}

According to this you can't change an elements namespace in an XmlDocument. This is also what #LocEngineer found in his comment. The referenced article mentions that the only way to do this is to save and reload the XmlDocument, which is exactly what you are doing.
If you are in a position to use XDoxument instead, it is possible. See this answer for a solution.

XDocument automatically indents files on parse and does not remove indent on save

I am seeking a help regarding file saving of XML file using XDocument (NOT XMLDocument).
So I have a xml file that does not have indentation (in fact it is 1 line). When I read this to XDocument using XDocument.Parse (after reading and storing string using StreamReader), the resulting XDocument is indented.
Alright, I thought it will be fine as long as if I can save it back to the file without indentation. However, even though I have
XmlWriterSettings writerSettings = new XmlWriterSettings();
writerSettings.NewLineOnAttributes = false;
writerSettings.NewLineHandling = NewLineHandling.None;
writerSettings.Indent = false;
and pass that in when I create XmlWriter
using (var writer = XmlWriter.Create(u.ToFileSystemPath(), settings))
{
xd.Save(writer);
}
The resulting XML file still has indentation. When I am debugging on Visual studio, I noticed that the writer is a class XmlWellFormedWriter. Does this have something to do with my result? Any help would be appreciated.
Thank you.

SaveOptions are available on Save() as well as ToString().
string xmlstring =
#"<Top>
<First>1</First>
<Second>Dude</Second>
<Third>Now</Third>
</Top>";
XDocument doc = XDocument.Parse(xmlstring);
doc.Save(#"C:\temp\noIndet.xml", SaveOptions.DisableFormatting);
// string noIndent = doc.ToString(SaveOptions.DisableFormatting);
Output:

Why are all of my line-breaks changing from "/r/n" to "/n/" and how can I stop this from happening?

I am saving my files as xml documents, using XDocument.Save(path), and after saving and loading a document all of the line breaks have changed from "/r/n" to "/n/". Why is this happening and how can I fix it?

You can use XmlWriterSettings to control what your line-break characters are:
XmlWriterSettings xws = new XmlWriterSettings();
xws.NewLineChars = "\r\n";
using (XmlWriter xw = XmlWriter.Create("whatever.xml", xws))
{
xmlDocumentInstance.Save(xw);
}
Whatever you're using to read in your XML might be normalizing your line endings.

If you set the PreserveWhiteSpace property on your XmlDocument object before calling Load() and Save() then this will not happen:
var doc = new XmlDocument();
doc.PreserveWhitespace = true;
doc.Load("foo.xml");
...
doc.Save("bar.xml"); // Line endings will not be altered

Dataset -> XML Document - Load DataSet into an XML Document - C#.Net

I'm trying to read a dataset as xml and load it into an XML Document.
XmlDocument contractHistoryXMLSchemaDoc = new XmlDocument();
using (MemoryStream ms = new MemoryStream())
{
//XmlWriterSettings xmlWSettings = new XmlWriterSettings();
//xmlWSettings.ConformanceLevel = ConformanceLevel.Auto;
using (XmlWriter xmlW = XmlWriter.Create(ms))
{
xmlW.WriteStartDocument();
dsContract.WriteXmlSchema(xmlW);
xmlW.WriteEndDocument();
xmlW.Close();
using (XmlReader xmlR = XmlReader.Create(ms))
{
contractHistoryXMLSchemaDoc.Load(xmlR);
}
}
}
But I'm getting the error - "Root Element Missing".
Any ideas?
Update
When i do xmlR.ReadInnerXML() it is empty. Does anyone know why?
NLV

A few things about the original code:
You don't need to call the write start and end document methods: DataSet.WriteXmlSchema produces a complete, well-formed xsd.
After writing the schema, the stream is positioned at its end, so there's nothing for the XmlReader to read when you call XmlDocument.Load.
So the main thing is that you need to reset the position of the MemoryStream using Seek. You can also simplify the whole method quite a bit: you don't need the XmlReader or writer. The following works for me:
XmlDocument xd = new XmlDocument();
using(MemoryStream ms = new MemoryStream())
{
dsContract.WriteXmlSchema(ms);
// Reset the position to the start of the stream
ms.Seek(0, SeekOrigin.Begin);
xd.Load(ms);
}

XmlDocument contractHistoryXMLSchemaDoc = new XmlDocument();
using (MemoryStream ms = new MemoryStream())
{
dsContract.WriteXml(ms);
ms.Seek(0, SeekOrigin.Begin);
using(XmlReader xmlR = XmlReader.Create(ms))
{
contractHistoryXMLSchemaDoc.Load(xmlR);
}
}

All you really need to do is to call contractHistoryXMLSchemaDoc.Save(ms). That will put the xml into the MemoryStream.
XmlDocument contractHistoryXMLSchemaDoc = new XmlDocument();
using (MemoryStream ms = new MemoryStream())
{
contractHistoryXMLSchemaDoc.Save(ms);
ms.Flush();
}

Here you go.
If from the naming convention of your variables, (not though the question you asked, which appears to change...), you need to load the XML scema of the data set into the XML document that you named with schema, below is the code to load schema of the dataset into an XMLDocument.
I want the schema of the dataset in a separate XML document. – NLV Apr 19 '10 at 12:01
Answer:
XmlDocument contractHistoryXMLSchemaDoc = new XmlDocument();
using (MemoryStream ms = new MemoryStream())
{
dsContract.WriteXmlSchema(ms);
ms.Seek(0, SeekOrigin.Begin);
contractHistoryXMLSchemaDoc.Load(ms);
}
If you are looking for how to load the dataset table data into an XML document (note I removed the word Schema from the XMLDocument variable name)
Your Question:
Sorry, i dont get you. I need to get the xml of that dataset into an xml document. – NLV Apr 19 '10 at 11:56
Answer:
XmlDocument contractHistoryXMLDoc = new XmlDocument();
using (MemoryStream ms = new MemoryStream())
{
dsContract.WriteXml(ms,XmlWriteMode.IgnoreSchema);
ms.Seek(0, SeekOrigin.Begin);
contractHistoryXMLDoc.Load(ms);
}
If you want the Schema and data set in separate documents, the code is above.
If you want just the schema or just the data in and xml document, use the above bit of code that pertains to your question.
If you want both the XML Schema and the Data in the same XMLDocument, then use this code.
XmlDocument contractHistoryXMLDoc = new XmlDocument();
using (MemoryStream ms = new MemoryStream())
{
dsContract.WriteXml(ms,XmlWriteMode.WriteSchema);
ms.Seek(0, SeekOrigin.Begin);
contractHistoryXMLDoc.Load(ms);
}
Your Question:
But I'm getting the error - "Root Element Missing".
Any ideas?
Update
When i do xmlR.ReadInnerXML() it is empty. Does anyone know why?
NLV
Answer:
There are underlying issues in your code in the way you think it is working, which means it is not really creating the XMLSchema and XmlData (dsContract), which is why you are seeing a blank XMLDocument.
It would probably help you to fully explain what you wish, and then not reply to everyone using partial sentences of which are misunderstood and your having to keep replying with more partial sentences.

Creating an XML Element object from an XML Writer in C#

I'm writing a Windows service in C#. I've got an XmlWriter which is contains the output of an XSLT transformation. I need to get the XML into an XMLElement object to pass to a web service.
What is the best way to do this?

You do not need an intermediate string, you can create an XmlWriter that writes directly into an XmlNode:
XmlDocument doc = new XmlDocument();
using (XmlWriter xw = doc.CreateNavigator().AppendChild()) {
// Write to `xw` here.
// Nodes written to `xw` will not appear in the document
// until `xw` is closed/disposed.
}
and pass xw as the output of the transform.
NB. Some parts of the xsl:output will be ignored (e.g. encoding) because the XmlDocument will use its own settings.

Well, an XmlWriter doesn't contain the output; typically, you have a backing object (maybe a StringBuilder or MemoryStream) that is the dumping place. In this case, StringBuilder is probably the most efficient... perhaps something like:
StringBuilder sb = new StringBuilder();
using (XmlWriter writer = XmlWriter.Create(sb))
{
// TODO write to writer via xslt
}
string xml = sb.ToString();
XmlDocument doc = new XmlDocument();
doc.LoadXml(xml);
XmlElement el = doc.DocumentElement;

If you provide a writer, you provide a repository where an output generator is transferring data, thus the replay of Richard is good, you don't really need a string builder to send data from a reader to an XmlDocument!