Xml

Xslt

To debug in Visual Studio 2005, use the XslCompiledTransform(true) constructor.

XslCompiledTransform transformer = new XslCompiledTransform();
transformer.Load("transform.xslt");
XsltArgumentList args = new XsltArgumentList();
args.AddParam("ID", "", "Value"); //second argument is namespace
transformer.Transform("data.xml", args, Response.OutputStream);

Formatted XmlDocument

private static string FormattedXml(XmlNode doc) //quickly format xml string
{
    MemoryStream ms = new MemoryStream(); //could use stringbuilder but always utf16
    XmlWriterSettings settings = new XmlWriterSettings();
    settings.Indent = true; //in 1.1 an xmlTextwriter with Formatting= Formatting.Indented
    settings.Encoding = Encoding.UTF8;
    using (XmlWriter writer = XmlWriter.Create(ms, settings))
    {
        doc.WriteTo(writer);
    }
    return Encoding.UTF8.GetString(ms.ToArray());
}

AddElement

Everybody writes a version of this when using XmlDocument. Makes it easy to chain together too.

private static XmlElement AddElement(XmlNode parent, string name)
{
    XmlElement element = parent.OwnerDocument.CreateElement(name);
    parent.AppendChild(element);
    return element;
}

XPath in XDocument

XPath is often more readable for complex parsing. The extension requires "using System.Xml.XPath;"

//using System.Xml.Linq;
var webConfig = XDocument.Load(fileName);
//using System.Xml.XPath;
XElement e = webConfig.XPathSelectElement("configuration/system.web/httpModules/add[@name='AuthModule']");

XHTML

Doesn't work if the page uses html entities ( ) and non-closing tags (look out for <script />), but otherwise this is okay.

XmlDocument doc = new XmlDocument();
doc.PreserveWhitespace = true; //if saving
doc.XmlResolver = null; //we don't want to resolve the w3c DTD
XmlNamespaceManager ns = new XmlNamespaceManager(doc.NameTable);
ns.AddNamespace("html", "http://www.w3.org/1999/xhtml");

To use entities, create a custom XmlResolver

SQL Server 2005

FOR XML returns Xml Fragments (no root node- append , root('rootName')).
Rename columns with aliases (and tables for xml auto).

SQLServer	Clause	Result
2000+	For Xml Raw[('ElementName')]	<row NAME="RED"/> <ElementName NAME="RED"/> with for xml Raw('ElementName')
2000+	For Xml Auto [,Elements]	<TABLENAME NAME="RED"/> NB joined tables are nested	<TABLENAME> <NAME>RED<NAME> </TABLENAME>
2005+	For Xml Path	Easy elements/attributes and nesting- use xpath in alias `select '1' as '@id', 'New York' as 'address/city/@value'` Keep together: `select '1' as '@id', 'New York' as 'address/city', 'John' as 'name', 'NY' as 'address/state' for xml path` has two adddress nodes NULLS: `for xml path, elements xsinil` to get "null" elements: <CouldbeNull xsi:nil="true" /> WITH NAMESPACES('uri' as prefix)

XQuery: For the SQL2005 xml data type, use xmlColumn.query('/xpath') in the sql.
Where xmlColumn.exists('/root/possiblenode')=1
Namespaces: xmlColumn.query(declare namespace a='uri'; /a:element)
Xml contsriuction (with curly braces): xmlColumn.query('<NewRoot> { /OldRoot } </NewRoot>')
There's a for-loop construct
xmlColumn.query('{ for $n in /root/a return string($n) }')
There's even xml DML: xmlDolumn.modify('replace value of (/root/a)[1] with "New Text")