The System.Xml.XmlDocument Class

Supported Versions

Public Members

Overview

XMLDocument is a fundamental building block of the System.Xml class hierarchy. It essentially inherits and extends the XMLNode class, and represents a W3C DOM-compliant XML document in its entirety. Once created or loaded into memory, its contents can be accessed, edited, and manipulated.

Key methods of this class include Load and LoadXml. The former is primarily used to retrieve XML using a resource path, whereas the latter accepts a string value consisting of an XML document or fragment. The InnerText, InnerXml, and OuterXml properties conveniently allow you to retrieve values and XML markup from a document. Below are three examples demonstrating the use of the XMLDocument class.

Example (VB.NET): How to load an XML document into memory using the XMLDocument.Load method.

This first example simply uses the Load method and InnerText property of the XMLDocument class to load an existing document into memory and display its contents.

        Dim objDoc As New System.Xml.XmlDocument

        objDoc.Load("c:\sample.xml")

        TextBox1.Text = objDoc.InnerText

Example (VB.NET): How to display XMLDocument properties.

This example uses the XMLDocument class to load an XML document and displays a series of properties

        Dim objDoc As New System.Xml.XmlDocument

        Dim strProperties As String

        objDoc.Load("c:\sample.xml")

        strProperties = "XmlDocument.BaseURI: " & objDoc.BaseURI & CrLf

        strProperties &= "XmlDocument.DocumentElement.Name: " & objDoc.DocumentElement.Name & CrLf

        strProperties &= "XmlDocument.HasChildNodes: " & objDoc.HasChildNodes & CrLf

        strProperties &= "XmlDocument.IsReadOnly: " & objDoc.IsReadOnly & CrLf

        strProperties &= "XmlDocument.Name: " & objDoc.Name & CrLf

        strProperties &= "XmlDocument.NodeType: " & objDoc.NodeType & CrLf

        TextBox1.Text = strProperties

Example (VB.NET): How to use the XMLDocument.LastChild.AppendChild method to append a new node to an XML document.

This third example actually changes the structure of the loaded document by first creating an XMLNode object using the XMLDocument.CreateNode method, and then assigning this node a value via its InnerText property. The node is finally appended and its value displayed, using the XMLDocument.LastChild.AppendChild method and the XMLDocument.OuterXml property.

        Dim objDoc As New System.Xml.XmlDocument

        Dim objNode As System.Xml.XmlNode

        objDoc.Load("c:\sample.xml")

        objNode = objDoc.CreateNode(XmlNodeType.Element, "SampleNode", "")

        objNode.InnerText = "Sample Data"

        objDoc.LastChild.AppendChild(objNode)

        TextBox1.Text = objDoc.OuterXml