Obtener dato de un nodo xml

Public Function nodo(ByVal archivo As String, ByVal tag As String, ByVal deep As Integer) As String
        Dim sr As New StreamReader(Directory.GetCurrentDirectory & "\" & Form1.sdp & archivo, Encoding.UTF8)
        Dim i As Integer = 0
        Dim dato As String = ""
        Dim linea As String = sr.ReadLine()
        While linea IsNot Nothing
            If linea.Contains(tag) Then
                i += 1
            End If
            If i = deep Then
                dato = linea.Substring(tag.Length, linea.Length - 2 * tag.Length - 1)
                Exit While
            End If
            linea = sr.ReadLine().Trim
        End While
        sr.Close()
        sr.Dispose()
        Return dato
    End Function