Comments

<%-- This is a comment --%>
<%-- This is a
multi-line comment --%>

Page directives

<%@ Page Title="Products" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true"  CodeBehind="ProductList.aspx.cs" Inherits="WingtipToys.ProductList" %>

Directive tag

<%: Page.Title %>
<a href="ProductDetails.aspx?productID=<%#:Item.ProductID%>">
<span>
    <%#:Item.ProductName%>
</span>

Highlighted C# inside scripts

This requires the C# component to be loaded. On this page, check C# before checking ASP.NET should make the example below work properly.

<script runat="server">
    // The following variables are visible to all procedures
    // within the script block.
    String str;
    int i;
    int i2;

    int DoubleIt(int inpt)
    {
        // The following variable is visible only within
        // the DoubleIt procedure.
        int factor = 2;

        return inpt * factor;
    }
</script>