Rotating Messages with the ActiveX Timer and Text Controls

Steve Kirk
Microsoft Developer Network Technology Group

July 27, 1996

Contents

Introduction
Creating Instances of the Objects
Creating the Script
Text Control Events, Methods, and Properties

Abstract

This article explains how the ActiveX™ Text control can be used with the ActiveX Timer control and Microsoft® Visual Basic® Scripting Edition (VBScript) to create a continuously changing text message.

Introduction

In this article, we'll explain how to cycle a text object, randomly, through a series of stored messages by implementing ActiveX objects and Visual Basic Scripting Edition. We will first create instances of the ActiveX Timer and Text objects in Hypertext Markup Language (HTML) and initialize the properties of the objects. We will then add VBScript code to the HTML page to store data and to provide methods for the ActiveX objects.

To complete this example, you will need the ActiveX Text and Timer controls, which can be found in the Microsoft ActiveX SDK (the ActiveX SDK can be downloaded from the SDK section of the MSDN Online Web site at http://www.microsoft.com/msdn/), and a scripting language such as Microsoft Visual Basic Scripting Edition or Netscape Communications JavaScript. In this example, we will be using Visual Basic Scripting Edition as our scripting language.

Creating Instances of the Objects

The following HTML code fragment creates the ActiveX Text control and initializes its properties. Using the HTML <OBJECT> tag, we define this object as txtFactoid and indicate that it will be an ActiveX Text control by specifying its class ID. (The class ID can be obtained from the registry or the type library of the control, or it can be generated by the ActiveX Control Pad, available from http://www.microsoft.com/workshop/author/cpad/.) We also set properties to determine the size and font of the Text control using the <PARAM> tag.

<OBJECT ID="txtFactoid" WIDTH=130 HEIGHT=130
CLASSID="CLSID:8BD21D10-EC42-11CE-9E0D-00AA006002F3">
    <PARAM NAME="VariousPropertyBits" VALUE="-1400879085">
    <PARAM NAME="ScrollBars" VALUE="2">
    <PARAM NAME="Size" VALUE="6350;3457">
    <PARAM NAME="SpecialEffect" VALUE="0">
    <PARAM NAME="FontName" VALUE="Garamond">
    <PARAM NAME="FontCharSet" VALUE="0">
    <PARAM NAME="FontPitchAndFamily" VALUE="2">
    <PARAM NAME="FontWeight" VALUE="0">
    <PARAM NAME="FontHeight" VALUE="200">
</OBJECT>

The next piece of code is the <OBJECT> tag for the ActiveX Timer object. The key properties are the class ID, which identifies this object as an ActiveX Timer, the interval, which specifies how often (in milliseconds) the timer fires, and the object ID, which is used to associate this timer with the VBScript subroutine that is called each time the timer fires.

<OBJECT ID="tmrFactoid" WIDTH=0 HEIGHT=0
CLASSID="CLSID:59CCB4A0-727D-11CF-AC36-00AA00A47DD2">
   <PARAM NAME="Interval" VALUE="2000">
</OBJECT>

(For more information on the ActiveX Timer control, see "Creating a Slide Show Using the ActiveX Timer Control".)

Creating the Script

The following VBScript code is placed between the <SCRIPT> and </SCRIPT> tags on the HTML page. The first statement dimensions an array to hold the strings for the various titles. Strings are then assigned to the elements of the array:

<SCRIPT LANGUAGE="VBScript">
dim strFactoids(14)
strFactoids(0) = "Scientists have…" 
'lines for elements (1) to (13) skipped here
strFactoids(14) = "Jojoba, a shrub related to boxwood…"

In Visual Basic Scripting Edition, the Web page is an implied object called Window, and one of its events is the Load event. The link between object events and the corresponding VBScript code is a naming convention that combines the object ID with the event, separated by an underscore. Following this convention, we can see that subroutine Window_Onload will be called when the Web page loads. Subroutine Window_OnLoad first calls Randomize, to initialize the seed number for the RND function, then calls SetFactoid to initialize txtFactoid:

sub Window_Onload()
'Init random number sequence
Randomize
'Set inital value of txtFactoid
Call SetFactoid
end sub

Subroutine tmrFactoid_Timer is called when the Timer event for the Timer object tmrFactoid occurs. Note that the interval property of tmrFactoid determines how often, in milliseconds, this event happens:

Sub tmrFactoid_Timer()
Call SetFactoid
end sub

The final subroutine, SetFactoid, picks one of the text strings stored in the strFactoid() array and uses it to set the value property of txtFactoid:

Sub SetFactoid()
   txtFactoid.Locked = False
   txtFactoid.Value = strFactoids(Int((UBound(strFactoids) + 1) * Rnd))
end sub

Text Control Events, Methods, and Properties

The tables below list the events, methods, and properties supported by the Text control. For a similar listing for the ActiveX Timer control, please see "Creating a Slide Show Using the ActiveX Timer Control".

Table 1. ActiveX Text Control Events

Table 2. ActiveX Text Control Methods

Table 3. ActiveX Text Control Properties