In developing a Web Application, you may want to declare a table of data
for use by one or more pages at application level scope. This article
demonstrates how to declare, populate, and reference an array that has been
declared at application level scope.
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Declaring Arrays at Application Level Scope
Repeat the following steps for a demonstration on referencing arrays with
application scope.
| 1. | On a computer that is running Active Server Pages, create a folder named ATEST and configure Internet Information Server (IIS) to recognize this directory as a virtual root with execute permissions.
|
| 2. | Create a file in this directory named Global.asa. Copy and paste the
following code into this file:
<SCRIPT LANGUAGE=VBSCRIPT RUNAT=SERVER>
SUB Application_OnStart
' This script executes when the first user comes to the site
' or the global.asa is modified.
' A simple fixed size array
Dim aFixed(3)
aFixed(1) = "Fixed"
aFixed(2) = "Size"
aFixed(3) = "Array"
' Cache the array as a member of the Application variables collection.
Application("aFixed") = aFixed
' Declare a dynamic (resizable) array.
Dim aColors()
' Allocate storage for the array.
Redim aColors(16)
' Store values representing a simple color table
' to each of the elements.
aColors(1) = "RED" ' [#FF0000]
aColors(2) = "GREEN" ' [#008000]
aColors(3) = "BLUE" ' [#0000FF]
aColors(4) = "AQUA" ' [#00FFFF]
aColors(5) = "BLACK" ' [#000000]
aColors(6) = "FUCHSIA" ' [#FF00FF]
aColors(7) = "GRAY" ' [#808080]
aColors(8) = "LIME" ' [#00FF00]
aColors(9) = "MAROON" ' [#800000]
aColors(10) = "NAVY" ' [#000080]
aColors(11) = "OLIVE" ' [#808000]
aColors(12) = "PURPLE" ' [#800080]
aColors(13) = "SILVER" ' [#C0C0C0]
aColors(14) = "TEAL" ' [#008080]
aColors(15) = "YELLOW" ' [#FFFF00]
aColors(16) = "WHITE" ' [#FFFFFF]
' Cache the array as a member of the Application variables collection.
Application("aColors") = aColors
END SUB
</SCRIPT>
|
| 3. |
Create a file in the same directory named Color.asp. Copy and paste the
following code into the file:
<%@ LANGUAGE="VBSCRIPT" %>
<HTML>
<BODY>
<H3>Arrays as Members of the Application variables collection.</H3>
<%
if IsArray(Application("aColors")) then
%>
<H3>A Resizable Array</H3>
<%
' Put a reference to the array in a temporary variable
' for easy access.
aColors = Application("aColors")
nColors = UBound(aColors)
%>
<TABLE BGCOLOR=BLACK>
<%
for i = 1 to nColors
cColor = aColors(i)
if cColor = "BLACK" then
cBGColor = "WHITE"
else
cBGColor = "BLACK"
end if
%>
<TR>
<TD BGCOLOR=<% =cBGColor %>>
<FONT COLOR=<% =cColor %>><% =cColor %></FONT>
</TR>
<% next %>
</TABLE>
<%
else
Response.Write("Application('aColors') is not an array! <BR>")
end if
if IsArray(Application("aFixed")) then
%>
<H3>A Fixed Size Array</H3>
<%
aFixed = Application("aFixed")
for i = 1 to UBound(aFixed)
Response.Write(aFixed(i) & "<BR>")
next
else
Response.Write("Application('aFixed') is not an array! <BR>")
end if
%>
</BODY>
</HTML>
|
| 4. | Save the files, launch a client browser such as Internet Explorer, and load the Active Server Page using a path similar to the following:
http://<server>/Atest/Color.asp
|
The browser should display the contents of the arrays, which were stored at
the application level.
Observe that, in the above sample, it is only during application startup that the contents of the variables collection of the
Application object is altered. For that reason, there is no need to lock the
Application object. As with any other element of the variables collection of the
Application object, if the contents of the array were modified by another Active Server Page or via a session-level event, the
Application object would need to be locked. For more information on the
Lock and
Unlock methods of the
Application object, see the Active Server Pages Roadmap.
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Active Server Pages Online documentation
For the latest Knowledge Base articles and other support information on
Visual InterDev and Active Server Pages, see the following page on the
Microsoft Technical Web Support site:
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