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Message: <blockquote data-quote="gosmart" data-source="post: 15029491" data-attributes="member: 314820">Now that you’ve seen that you can move around in the XML document and even get the values of theelements, let’s examine how to change the structure of the document by adding nodes to the booksdocument you’ve been using until now.To insert new elements in the list, you need to examine the new methods that are placed on theXmlDocument and XmlNode classes, shown in Table 22-4. The XmlDocument class has methods thatenable you to create new XmlNode and XmlElement instances, which is nice because both of theseclasses have only a protected constructor, which means you cannot create an instance of either directlywith new.The methods in Table 22-4 are all used to create the nodes themselves, but after calling any of them youhave to do something with them before they become interesting. Immediately after creation, the nodescontain no additional information, and they are not yet inserted into the document. To do either, youUsing XML in Your Application ❘ 741should use methods that are found on any class derived from XmlNode (including XmlDocument andXmlElement), described in the following table:METHOD DESCRIPTIONAppendChild Appends a child node to a node of type XmlNode or a derived type. Rememberthat the node you append appears at the bottom of the list of children of thenode on which the method is called. If you don’t care about the order of the children,there’s no problem; if you do care, remember to append the nodes in thecorrect sequence.InsertAfter Controls exactly where you want to insert the new node. The method takes twoparameters — the first is the new node and the second is the node after whichthe new node should be inserted.InsertBefore Works exactly like InsertAfter, except that the new node is inserted beforethe node you supply as a reference.TABLE 22-4: Methods for Creating NodesMETHOD DESCRIPTIONCreateNode Creates any kind of node. There are three overloads of the method, two ofwhich enable you to create nodes of the type found in the XmlNodeTypeenumeration and one that enables you to specify the type of node to use asa string. Unless you are quite sure about specifying a node type other thanthose in the enumeration, use the two overloads that use the enumeration. Themethod returns an instance of XmlNode that can then be cast to the appropriatetype explicitly.CreateElement A version of CreateNode that creates only nodes of the XmlDocument variety.CreateAttribute A version of CreateNode that creates only nodes of the XmlAttribute variety.CreateTextNode Creates — yes, you guessed it — nodes of the type XmlTextNodeCreateComment This method is included here to highlight the diversity of node types that canbe created. This method doesn’t create a node that is actually part of the datarepresented by the XML document, but rather is a comment meant for anyhuman eyes that might have to read the data. You can pick up comments whenreading the document in your applications as well.In the Following Try It Out, you build on the previous example and insert a book node in the books.xmldocument. There is no code in the example to clean up the document (yet), so if you run it several timesyou will probably end up with a lot of identical nodes.742 ❘</blockquote>

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