Visual Basic

 <InterfaceType(ComInterfaceType.InterfaceIsDual)> _
Public Interface ComIF
   'test function
    Function XTest(ByRef XTRange As XL.Range) As Object

' Class that implements the Interface
<Guid("9FEB08E8-B561-4e9e-9990-C73D02B206C5"), _
ClassInterface(ClassInterfaceType.None), ProgId("HumarFunctions.Functions1")> _
Public Class Functions1 : Implements ComIF

   Public Function XTest(ByRef XTRange As XL.Range) As Object Implements ComIF.XTest
        On Error GoTo MyErr

<various bits of code to try and return the calling cell address
none of which work !>

        Exit Function
MyErr:
        XTest = CVErr(CVErrEnum.ErrNA)
    End Function
End Class

If Clipboard.ContainsData("XML Spreadsheet") = True Then
            Dim ms As MemoryStream = CType(Clipboard.GetData("XML Spreadsheet"), MemoryStream)
            Dim b(CInt(ms.Length)) As Byte
            ms.Read(b, 0, CInt(ms.Length))
            Debug.Write(CStr(System.Text.UTF7Encoding.UTF8.GetString(b)))
            '=====================================================
            Dim m_xmld As XmlDocument
            Dim m_nodelist As XmlNodeList
            Dim m_node As XmlNode
            'Create the XML Document
            m_xmld = New XmlDocument()

            'Load the Xml content from the clipboard
            m_xmld.LoadXml(System.Text.UTF8Encoding.UTF8.GetString(b))

            'Get the list of name nodes 
            m_nodelist = m_xmld.SelectNodes("/Workbook/Worksheet/Row")

            'Loop through the nodes
            For Each m_node In m_nodelist
                'Row data code here

            Next
            '=====================================================

        Else
            MsgBox("No XML Spreadsheet data on clipboard")
        End If