You can use the Application object to share
information among all users of a given application. An ASP-based
application is defined as all the .asp files in a virtual directory
and its subdirectories. Because the Application object can be
shared by more than one user, there are Lock and Unlock methods to
ensure that multiple users do not try to alter a property
||The Contents.Remove method deletes an item
from the Application object's Contents
||The Contents.RemoveAll method deletes all
items from the Application object's Contents
||The Lock method prevents other clients from
modifying Application object properties.
||The Unlock method allows other clients to
modify Application object properties.
Scripts for the preceding events are declared in
the Global.asa file. For more information about these events and
the Global.asa file, see the Global.asa Reference.
You can store values in the Application
Collections. Information stored in the Application
collections is available throughout the application and has
application scope. The following script demonstrates storage of two
types of variables.
Application("greeting") = "Welcome to My Web World!"
Application("num") = 25
Each of these variables would be members of the
Application Contents Collection.
You can also assign a component instance to a
variable that has application scope. If you assign a component
instance to a variable with the Server.CreateObject method,
the variable will be a member of the Application.Contents
collection. If the variable is assigned with the <OBJECT>
tag, the variable will be a member of the Application
You should be careful about assigning component
instances to variables with application scope, because some
components are not designed to be given application scope. For more
information, see the Platform SDK.
If you assign a component instance to a variable
in the Application Contents Collection, and use Visual
Basic® Scripting Edition (VBScript) as your primary
scripting language, you must use the Set keyword. This is
illustrated in the following script.
<% Set Application("Obj1") = Server.CreateObject("MyComponent") %>
You can then reference the methods and properties
MyComponent on subsequent Web pages by using this
<% Application("Obj1").MyObjMethod %>
or by extracting a local copy of the object and
using the following
Set MyLocalObj1 = Application("Obj1")
Another way to create objects with application
scope is by using the <OBJECT> tag in the Global.asa file.
For more information, see the Global.asa Reference.
You cannot store a built-in object in the
Application object. For example, each of the following lines
returns an error.
Set Application("var1") = Session
Set Application("var2") = Request
Set Application("var3") = Response
Set Application("var4") = Server
Set Application("var5") = Application
Set Application("var6") = ObjectContext
You should be aware of the threading model used
by any components you give application scope. The threading model
used to develop the component will have a significant impact on
whether a component instance should be assigned to a variable in
one of the Application collections.
If you store an array in an Application
object, you should not attempt to alter the elements of the stored
array directly. For example, the following script does not
<% Application("StoredArray")(3) = "new value" %>
This is because the Application object is
implemented as a collection. The array element
StoredArray(3) does not
receive the new value. Instead, the value would be included in the
Application object collection, and would overwrite any
information that had previously been stored at that location.
It is strongly recommended that if you store an
array in the Application object,
you retrieve a copy of the array before retrieving or changing any
of the elements of the array. When you are done with the array, you
should store the array in the Application object again, so
that any changes you made are saved. This is demonstrated in the
'Creating and initializing the array.
MyArray(0) = "hello"
MyArray(1) = "some other string"
'Storing the array in the Application object.
Application("StoredArray") = MyArray
'Retrieving the array from the Application Object
'and modifying its second element.
LocalArray = Application("StoredArray")
LocalArray(1) = " there"
'Printing out the string "hello there."
'Re-storing the array in the Application object.
'This overwrites the values in StoredArray with the new values.
Application("StoredArray") = LocalArray
The following example uses the application
variable NumVisits to store the number of times that a
particular page has been accessed. The Lock method is called
to ensure that only the current client can access or alter
Calling the Unlock method then enables other users to access
the Application object.
Application("NumVisits") = Application("NumVisits") + 1
This application page has been visited <%= Application("NumVisits") %> times!