ASP Lesson 5:- ASP Application Object
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ASP Application Object
An ASP application on the Web may be a group of ASP files. The ASP files work
together to perform some purpose. The Application object in ASP is used to tie
these files together.
The Application object is used to store and access variables from any page,
just like the Session object. The difference is that ALL users share one Application
object, while with Sessions there is one Session object for EACH user.
The Application object should hold information that will be used by many pages
in the application (like database connection information). This means that you
can access the information from any page. It also means that you can change
the information in one place and the changes will automatically be reflected
on all pages.
ASP Store and Retrieve Application Variables
ASP application variables can be accessed and changed by any page in the application.
You can create Application variables in "Global.asa" like this:
<script language="vbscript" runat="server">
Sub Application_OnStart
application("vartime")=""
application("users")=1
End Sub
</script>
In the example above we have created two Application variables: "vartime"
and "users".
You can access the value of an Application variable like this:
There are
<%
Response.Write(Application("users"))
%>
active connections.
ASP Loops Through the Contents Collection
The Contents collection contains all application variables. You can loop through
the Contents collection, to see what's stored in it:
<%
dim i
For Each i in Application.Contents
Response.Write(i & "<br />")
Next
%>
If you do not know the number of items in the Contents collection, you can
use the Count property:
<%
dim i
dim j
j=Application.Contents.Count
For i=1 to j
Response.Write(Application.Contents(i) & "<br />")
Next
%>
ASP Loops Through the StaticObjects Collection
You can loop through the StaticObjects collection, to see the values of all
objects stored in the Application object:
<%
dim i
For Each i in Application.StaticObjects
Response.Write(i & "<br />")
Next
%>
ASP 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
%>
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