I'm trying to incorporate into my web pages who long the server took to generate the requested information. So far, I have had no luck on Google or any other developer forums. Below is some code I am working on but I am getting the error message BC30002: Type 'System.Diagnostics.Stopwatch' is not defined.

Code:
<%@ Page Language="vb" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Web.UI.Page" %>
<%@ Import Namespace="System.Diagnostics.Stopwatch" %>

<script runat="server">

dim sw as System.Diagnostics.Stopwatch =
System.Diagnostics.Stopwatch.StartNew()

Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)

Me.Label1.Text = sw.ElapsedSeconds
MyBase.Render(writer)

End Sub

</script>