BindingContext.Position is incrementing, but no change in text boxes?

Hey guys! It's me again!

And I'm pulling my hair out again... I've tried to debug this code myself, and I think it's something to do with how it's been written, but it was taken from a book "Computing Projects in Visual Basic.NET", so I'm pretty sure it's correct as far as code syntax goes.

Private Sub btnNext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNext.Click
        BindingContext(DataSet81, "Customers").Position += 1
End Sub

The actual issue is although the actual value of the position is increasing, it is not reflecting in the textboxes that are bound to DataSet81.

So for BindingContext.Position = 0, I have txtCustomerID.text = 1, but when I click the button, the BindingContext.Position increases to 1, but the txtCustomerID.text STILL = 1.