Adding line breaks and indents to XmlDocument

Question

What is the right way of adding line breaks and indents when building an XmlDocument to make its output (called by xmlDocoment->DocumentElement->OuterXml) look like this:

<QualifyingProperties Target="#SignatureElem_0" xmlns="http://uri.etsi.org/01903/v1.3.2#">
    <SignedProperties Id="SignedPropertiesElem_0">

This is the way I build my XmlDocument:

XmlDocument^ xmlDoc = gcnew XmlDocument();
xmlDoc->PreserveWhitespace = true;

XmlNode^ nQualifyingProperties = xmlDoc->CreateNode(XmlNodeType::Element, "QualifyingProperties", "http://uri.etsi.org/01903/v1.3.2#");
xmlDoc->AppendChild(nQualifyingProperties);
XmlNode^ nodAttribute = xmlDoc->CreateNode(XmlNodeType::Attribute, "Target", "");
nodAttribute->Value = SignatureId;
nQualifyingProperties->Attributes->SetNamedItem(nodAttribute)

XmlNode^ nSignedProperties = xmlDoc->CreateNode(XmlNodeType::Element, "SignedProperties", "http://uri.etsi.org/01903/v1.3.2#");
nQualifyingProperties->AppendChild(nSignedProperties);
nodAttribute = xmlDoc->CreateNode(XmlNodeType::Attribute, "Id", "");
nodAttribute->Value = SignedPropertiesId;
nSignedProperties->Attributes->SetNamedItem(nodAttribute);

I found that this works for line breaks:

XmlNode^ linebreak = xmlDoc->CreateTextNode("\n");
nQualifyingProperties->AppendChild(linebreak );

But I'm not sure it's the right way. Is it? And what about indents (tabs)?

EDIT: I am adding this XmlDocument to SignedXml as DataObject (where it's going to be signed), therefore I can't control formatting of this particular element, and while it's not a big deal, it would be nice to make it work the way I want it to work.

Answer 1

I have figured it out. XmlDocument should be written to a Stream with XmlWriter using, like Pavel suggested, XmlWriterSettings with Indent property enabled. Like this:

XmlDocument^ xmlDocument = gcnew XmlDocument();
xmlDocument->PreserveWhitespace = true;

//add some elements

XmlWriterSettings settings = new XmlWriterSettings();
XmlWriterSettings.Indent = true;
XmlWriterSettings.IndentChars = "\t"; //tabs instead of spaces

Stream^ stream = gcnew MemoryStream(); //or FileStream to write an Xml file directly to disk

XmlWriter^ writer = XmlWriter::Create(stream, settings);
xmlDocument->WriteTo(writer);
writer->Close();