Namespace prefix and URI values can be obtained using the XPathNavigator.LookupPrefix(string) or XPathNavigator.LookupNamespace(string) method. For example, the following syntax inserts a sibling element by using the in-scope namespace xmlns:bk="http://www.contoso.com/books":

navigator.InsertElementBefore(navigator.Prefix, "pages", LookupNamespaceURI(navigator.Prefix), String.Empty)

This creates the new sibling <bk:pages/> element.

The following are important notes to consider when using the XPathNavigator.InsertElementBefore(string, string, string, string) method.

• If the namespace prefix specified is null or string.Empty, then the prefix for the namespace URI of the new element is obtained from the current namespaces in-scope. If there is no namespace prefix assigned to the specified namespace URI at the current scope, then a namespace prefix is automatically generated.

• The XPathNavigator.InsertElementBefore(string, string, string, string) method is valid only when the System.Xml.XPath.XPathNavigator is positioned on an element, text, processing instruction, or comment node.

• The XPathNavigator.InsertElementBefore(string, string, string, string) method does not affect the position of the System.Xml.XPath.XPathNavigator.