Page 236 - DCAP408_WEB_PROGRAMMING

Web Programming

Notes <%
dim i
For Each i in Application.StaticObjects
Response.Write(i & “<br />”)
Next
%>

Did u know? What is Staicobject collection?
The StaticObjects collection contains all of the objects created by using the <OBJECT> tags
within the scope of the Application object. You can use the collection to determine the
value of a specific property for an object or to iterate through the collection and retrieve
all properties for all static objects.
Lock and Unlock

You can lock an application with the “Lock” method. When an application is locked, the users
cannot change the Application variables (other than the one currently accessing it). You can
unlock an application with the “Unlock” method. This method removes the lock from the
Application variable:
<%
Application.Lock
‘do some application object operations
Application.Unlock
%>

Did u know? What is lock and unlock method?

The Lock method blocks other clients from modifying the variables stored in the
Application object, ensuring that only one client at a time can alter or access the Application
variables. If you do not call the Application.Unlock method explicitly, the server unlocks
the locked Application object when the .asp file ends or times out.

Pitfalls of Application Variables

Because only one instance of the Application object exists for the entire Web application,
application variables can be used more liberally than session variables. However, the Application
object does take up memory on the Web server, so only items that need to be stored in application
scope should be entered into the Application object. Two common pitfalls should be avoided
when working with application variables:
 Pitfall 1 - Do not put objects into the Application object unless vitally needed.

 Pitfall 2 - Only create application variables that are necessary. Why create unneeded
application variables when they’ll only waste your Web server’s memory?
A common pitfall among developers is wanting to place objects in the Application. One object
that is particularly alluring to put into the Application is the ADO Connection object, which is
used to connect to a database. We’ll discuss this object in detail during Week 3. It may seem like

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