XmlWriter.LookupPrefix Method
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
When overridden in a derived class, returns the closest prefix defined in the current namespace scope for the namespace URI.
Assembly: System.Xml (in System.Xml.dll)
Parameters
- ns
- Type: System.String
The namespace URI whose prefix you want to find.
Return Value
Type: System.StringThe matching prefix or Nothing if no matching namespace URI is found in the current scope.
| Exception | Condition |
|---|---|
| ArgumentException | ns is either Nothing or String.Empty. |
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()
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