c# .net change label text

Hello for I trying to use this code but for some reason it doesn’t work. Really need help with this. The problem is that the label doesn’t change name from “label” when I enter the site.

<asp:Label ID="Label1" runat="server" Text="label"></asp:Label>


<% 
    Label1.Text = "test";
    if (Request.QueryString["ID"] != null)
    {

        string test = Request.QueryString["ID"];
        Label1.Text = "Du har nu lånat filmen:" + test;
    }

     %>