dynamically set slider min and max values

Hi

I have a SQL query which will return the first and last years providing me a range.  

If I set the associated text box to the first year, this sets the minimum for the slider.

I then set the slider.maximum to the last year.

Unfortunately, the slider will not respond to input by the user.  Here is my code:

(FirstDate and LastDate are years formatted as a string and are found when I search the data base.  

The example I am working with FirstYear = "1600" and LastYear = "1615")

'now display range on slider as years
sliderStartLabel.Text = "Year " & FirstDate & " to "
slider_TextBox.Text = FirstDate
slider_TextBox_SliderExtender.Minimum = FirstDate

sliderEndLabel.Text = LastDate
slider_TextBox_SliderExtender.Maximum = LastDate

Any suggestions?  Thanks in advance for any help.