Starting Object Oriented Programming in VBScript
How to Create, Use and Reuse OOP Classes in a VBScript Application
Jul 26, 2009
Object oriented programming lies at the heart of many projects, and there is no reason that the VBScript application developer should not benefit from the advantages of using this technique. Advantages such as:
- the reuse of code
- the encapsulation of complex functionality
- the ability to change and add functionality without breaking the applications using the classes
In fact VBScript is a programming language that lends itself very nicely to object oriented programming and, in just a few minutes, the programmer can produce classes with properties that they can then go on and use in all of their applications.
Creating a Simple VBScript Class
A VBScript class is defined by using (rather obviously) the Class...End Class key words, for example:
This creates a empty class, but is not of much used yet. Therefore the properties can be added to it that define exactly what the class is meant to model:
It's worth noting that elements of the class can be either:
- public - available to all users of the class
- private - only available within the class itself
It's also worth storing the class in its own file at this point so that it can be reused again and again in different projects. So, for example the code above could be stored in the file "person.vbs" and it's then ready for use.
Using VBScript Classes
With the class placed in its own .vbs file it can then be used in a VBScript application. The easiest way to do this is to create a windows scripting file (for example "people.wsf") and then to load the class file:
The class can then be turned into an object by using the "new" method:
Here two person objects (Fred and Mary) have been created, and so their properties can be set:
And then these properties can be used elsewhere in the application:
All that's left to do is to is to run the VBScript code.
Running a VBScript Object Oriented Programming Application
The programmer runs the VBScript application by using Cscript:
The end result can be seen in figure 1 and it shows the way in which the class is created and used by the VBScript code stored within the Windows Scripting file and the programmer can, of course, use this class in any future applications that they write.
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