Adding dynamic controls

[fish]

I am new to .NET and am looking for a way to create a dynamic list of
textboxes. Basically, the form begins with a row of three textboxes and
the user can add another row (as many as they choose) by clicking on a
link ("add another row"). Here is a sub that I have that fires when the
page loads and also when the user clicks the link.

The form will display the additional rows when the user clicks the
link, but, unfortunately, every time the user does click to add another
row, I lose the post data. Is there a way around this or a better way
to accomplish this?
Private Sub generatePlaceholders()
Dim n As Int32 = rowNum.Value
Dim i As Int32

For i = 0 To n

Dim TextBox = New TextBox
TextBox.ID = "txtOne" + i.ToString
TextBox.EnableViewState = True
plcMedicine.Controls.Add(New TextBox)
plcMedicine.Controls.Add(New LiteralControl("<br>"))

Dim TextBox1 = New TextBox
TextBox1.ID = "txtTwo" + i.ToString
TextBox1.EnableViewState = True
plcDose.Controls.Add(New TextBox)
plcDose.Controls.Add(New LiteralControl("<br>"))

Dim TextBox2 = New TextBox
TextBox2.ID = "txtThree" + i.ToString
TextBox2.EnableViewState = True
plcQuantity.Controls.Add(New TextBox)
plcQuantity.Controls.Add(New LiteralControl("<br>"))

Next
End Sub