XmlWriter.WriteStartElement Method (String, String, String)
When overridden in a derived class, writes the specified start tag and associates it with the given namespace and prefix.
Assemblies: System.Xml (in System.Xml.dll)
System.Xml.ReaderWriter (in System.Xml.ReaderWriter.dll)
'Declaration Public MustOverride Sub WriteStartElement ( _ prefix As String, _ localName As String, _ ns As String _ )
The writer is closed.
There is a character in the buffer that is a valid XML character but is not valid for the output encoding. For example, if the output encoding is ASCII, you should only use characters from the range of 0 to 127 for element and attribute names. The invalid character might be in the argument of this method or in an argument of previous methods that were writing to the buffer. Such characters are escaped by character entity references when possible (for example, in text nodes or attribute values). However, the character entity reference is not allowed in element and attribute names, comments, processing instructions, or CDATA sections.
An XmlWriter method was called before a previous asynchronous operation finished. In this case, InvalidOperationException is thrown with the message “An asynchronous operation is already in progress.”
The following example writes out an XML fragment.
Option Strict Option Explicit Imports System Imports System.IO Imports System.Xml Public Class Sample Private Shared m_Document As String = "sampledata.xml" Public Shared Sub Main() Dim writer As XmlWriter = Nothing Try Dim settings As XmlWriterSettings = new XmlWriterSettings() settings.Indent = true writer = XmlWriter.Create (m_Document, settings) writer.WriteComment("sample XML fragment") ' Write an element (this one is the root). writer.WriteStartElement("book") ' Write the namespace declaration. writer.WriteAttributeString("xmlns", "bk", Nothing, "urn:samples") ' Write the genre attribute. writer.WriteAttributeString("genre", "novel") ' Write the title. writer.WriteStartElement("title") writer.WriteString("The Handmaid's Tale") writer.WriteEndElement() ' Write the price. writer.WriteElementString("price", "19.95") ' Lookup the prefix and write the ISBN element. Dim prefix As String = writer.LookupPrefix("urn:samples") writer.WriteStartElement(prefix, "ISBN", "urn:samples") writer.WriteString("1-861003-78") writer.WriteEndElement() ' Write the style element (shows a different way to handle prefixes). writer.WriteElementString("style", "urn:samples", "hardcover") ' Write the close tag for the root element. writer.WriteEndElement() ' Write the XML to file and close the writer. writer.Flush() writer.Close() Finally If Not (writer Is Nothing) Then writer.Close() End If End Try End Sub 'Main End Class 'Sample
.NET FrameworkSupported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
XNA FrameworkSupported in: 3.0, 2.0, 1.0
Portable Class LibrarySupported in: Portable Class Library
Supported in: Windows Phone 8.1
Supported in: Windows Phone Silverlight 8.1
Supported in: Windows Phone Silverlight 8