In classic ASP, the Server object was used to create COM component
instances by using the Server.CreateObject method. CreateObject still
exists in ASP.NET, along with a new method, CreateObjectFromClsid,
which uses a COM class ID (CLSID) instead of a ProgID to locate the
object to create. You should use both methods only when necessary,
since even though the details are handled for you, using these
methods incurs the cost of interoperating between COM and .NET
(unmanaged and managed) code. If there is a .NET alternative to using
a COM object, you will get better performance by sticking with the
.NET solution.
The ASP.NET version of the Server object also adds a number of useful
new utility functions, including HtmlDecode, UrlDecode, and
UrlPathEncode. HtmlDecode and UrlDecode are particularly welcome,
given that classic ASP developers were stuck either manually
implementing functionality to remove URL or HTML encoding from
strings that they'd encoded on another page or
relying on third party components or scripts to do so. Now this
functionality is built in.
In this chapter, we'll use the following code
listing as the basis for most examples in the chapter. Unless
otherwise noted, each example will consist of the Page_Load event
handler for that particular example. Any output messages or return
values displayed are shown as the Text property of the ASP.NET Label
named Message, or displayed by calling Response.Write.
<%@ Page Language="vb" %>
<html>
<head>
<script runat="server">
Sub Page_Load( )
'Example code will go here
End Sub
</script>
</head>
<body>
<asp:label id="Message" runat="server"/>
</body>
</html>
