XmlWriter.LookupPrefix Method

Parameters

• ns
  Type: System.String
  The namespace URI whose prefix you want to find.

Return Value

Type: System.String
The matching prefix or nulla null reference (Nothing in Visual Basic) if no matching namespace URI is found in the current scope.

Dim output As New StringBuilder()

Dim settings As New XmlWriterSettings()
settings.Indent = True
Using writer = XmlWriter.Create(output, 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.
    writer.Flush()
End Using

OutputTextBlock.Text = output.ToString()

StringBuilder output = new StringBuilder();

XmlWriterSettings settings = new XmlWriterSettings();
settings.Indent = true;
using (XmlWriter writer = XmlWriter.Create(output, 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", null, "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.
    string prefix = 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.
    writer.Flush();
}

OutputTextBlock.Text = output.ToString();