XmlWriter.WriteElementString Method (String, String, String)


Writes an element with the specified local name, namespace URI, and value.

Namespace:   System.Xml
Assembly:  System.Xml (in System.Xml.dll)

Public Sub WriteElementString (
	localName As String,
	ns As String,
	value As String


Type: System.String

The local name of the element.

Type: System.String

The namespace URI to associate with the element.

Type: System.String

The value of the element.

Exception Condition

The localName value is null or an empty string.


The parameter values are not valid.


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.”

For the asynchronous version of this method, see WriteElementStringAsync.

The following example uses several write methods to create 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


        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).

        ' Write the namespace declaration.
        writer.WriteAttributeString("xmlns", "bk", Nothing, "urn:samples")

        ' Write the genre attribute.
        writer.WriteAttributeString("genre", "novel")

        ' Write the title.
        writer.WriteString("The Handmaid's Tale")

        ' 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")

        ' 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.

        ' Write the XML to file and close the writer.

            If Not (writer Is Nothing) Then
            End If
        End Try

    End Sub 'Main 
End Class 'Sample

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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