Why does the label " lblNavLocation " for the record count does not update when I cli

[piscis]

Why does the label " lblNavLocation " for the record count does not update when I click a Row directly on the datagrid?

Private Sub objdsMachines_PositionChanged()
        Me.lblNavMachinesLocation.Text = (((Me.BindingContext(dataSetMachines, "Machines").Position + 1).ToString + " of  ") _
                    + Me.BindingContext(dataSetMachines, "Machines").Count.ToString)
    End Sub

But when I click a Navigation Bar buttons like Next or Previous then it does.

Private Sub btnNextRecord_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNextRecord.Click
        Me.BindingContext(dataSetReadings, "Readings").Position = (Me.BindingContext(dataSetReadings, "Readings").Position + 1)
        Me.objdsReadings_PositionChanged()
    End Sub