XML Literals

Visual Basic has a feature C# lacks: XML literals. You can write XML directly in code, embed expressions in it, and query it with special axis properties.

Building XML

Module Program
    Sub Main()
        Dim products = {("Tea", 3.5D), ("Coffee", 4.25D)}

        Dim catalog =
            <catalog updated="2025-03-09">
                <%= From p In products
                    Select <product price=<%= p.Item2 %>><%= p.Item1 %></product> %>
            </catalog>

        Console.WriteLine(catalog)
    End Sub
End Module

<catalog updated="2025-03-09">
  <product price="3.5">Tea</product>
  <product price="4.25">Coffee</product>
</catalog>

• The XML is checked by the compiler — a missing closing tag is a compile error.
• <%= expression %> embeds a value, or even a whole LINQ query that produces elements.
• The result is an XElement from LINQ to XML (System.Xml.Linq), which VB projects import automatically.

Reading XML with axis properties

Module Program
    Sub Main()
        Dim doc =
            <orders>
                <order id="1" status="paid"><total>42.50</total></order>
                <order id="2" status="pending"><total>18.00</total></order>
                <order id="3" status="paid"><total>7.25</total></order>
            </orders>

        For Each o In doc.<order>
            Console.WriteLine($"order {o.@id}: {o.@status}, {o.<total>.Value}")
        Next

        Dim paidTotal = Aggregate o In doc.<order>
                        Where o.@status = "paid"
                        Into Sum(Decimal.Parse(o.<total>.Value, Globalization.CultureInfo.InvariantCulture))
        Console.WriteLine($"paid total: {paidTotal}")
        Console.WriteLine(doc...<total>.Count())
    End Sub
End Module

order 1: paid, 42.50
order 2: pending, 18.00
order 3: paid, 7.25
paid total: 49.75
3

Loading and saving files

Module Program
    Sub Main()
        Dim settings = <settings><theme>dark</theme><fontSize>14</fontSize></settings>
        settings.Save("settings.xml")

        Dim loaded = XElement.Load("settings.xml")
        loaded.<theme>.Value = "light"
        Console.WriteLine(loaded.<theme>.Value & " " & CInt(loaded.<fontSize>.Value))
    End Sub
End Module

light 14

XML literals make VB a pleasant language for configuration files, reports, and data exchange with older systems. You can check XML output with the XML Formatter or XML Validator.