XObject.IXmlLineInfo.LineNumber Property

int IXmlLineInfo.LineNumber { get; }

string markup = @"<Root>
    <Child1 />
    <Child2 />
    <Child4 />
</Root>";

File.WriteAllText("Test.xml", markup);

XElement po = XElement.Load("Test.xml",
    LoadOptions.SetBaseUri | LoadOptions.SetLineInfo);

// add a node to the tree.
// the newly added node will not have line information.
po.Element("Child2").AddAfterSelf(new XElement("Child3"));

string[] splitUri = po.BaseUri.Split('/');
Console.WriteLine("BaseUri: {0}", splitUri[splitUri.Length - 1]);
Console.WriteLine();
Console.WriteLine("{0}{1}{2}",
    "Element Name".PadRight(20),
    "Line".PadRight(5),
    "Position");
Console.WriteLine("{0}{1}{2}",
    "------------".PadRight(20),
    "----".PadRight(5),
    "--------");
foreach (XElement e in po.DescendantsAndSelf())
    Console.WriteLine("{0}{1}{2}",
        ("".PadRight(e.Ancestors().Count() * 2) + e.Name).PadRight(20),
        ((IXmlLineInfo)e).HasLineInfo() ?
            ((IXmlLineInfo)e).LineNumber.ToString().PadRight(5) :
            "",
        ((IXmlLineInfo)e).HasLineInfo() ?
            ((IXmlLineInfo)e).LinePosition.ToString() :
            "No Line Information");

BaseUri: Test.xml

Element Name        Line Position
------------        ---- --------
Root                1    2
  Child1            2    6
  Child2            3    6
  Child3            No Line Information
  Child4            4    6