NEED Help, new to ASP and C#

[JCode]

I am trying to get a handle on ASP and C#. I am very familiar with php, and i'm trying to do some stuff that i can easily do in php. first
i'm trying to diplay a dropdownlist with numbers 1 through 5 in them, then i would like to display a textbox as many times as the numbers selected on the dropdown. my code looks like this.

<asp:dropdownlist id="num_items" style="Z-INDEX: 101; LEFT: 24px; POSITION: absolute; TOP: 360px"runat="server" AutoPostBack="True">
<asp:ListItem Value="1">1</asp:ListItem>
<asp:ListItem Value="2">2</asp:ListItem>
<asp:ListItem Value="3">3</asp:ListItem>
<asp:ListItem Value="4">4</asp:ListItem>
<asp:ListItem Value="5">5</asp:ListItem>
</asp:dropdownlist>

<asp:textbox id="txt_spec_name" style="Z-INDEX: 107; LEFT: 24px; POSITION: absolute; TOP: 432px"runat="server" Width="376px"></asp:textbox>

Now from the number selected in the num_items dropdownlist, i want it to display the textbox that many times, and make sure i know exactly which one is which, kind of like a variable in the id. can anyone help

[sde]

this isn't going to be much help, but i love c#, but i hate asp.net!
wouldn't it be something like this?

<script runat="server">
void Page_Load(object sender, EventArgs e)
{
  if (!IsPostBack)
  {
    txt_spec_name.Text = num_items.SelectedItem.ToString();
  }
}
</script>

i'm not 100% sure on this one, and i can't test it right now.