A collection of variables of the same data type is a very efficient data structure and easy to work with. Did you know that you can also define your own custom collections? Here is how!

What is a collection?

A collection is a stack of objects of the same type, “chained” one after the other.

As you add an object to the collection, it assumes the next index in sequence – added as the next “link” in the “chain”.

The collection is an easy to use data structure. It requires no declaration of the anticipated size of the “chain” in advance....

Instead of remembering numeric codes – label them with meaningful words. This way your code will flow from your fingers just as you speak, and your program will be clear and readable. Let us understand enumerations.

What are Enumerations?

Simply put, enumeration is about naming sets of related constant numbers.

You probably already worked with enumerations. For example, the Application.Calculation property is numeric. It holds a number representing the calculation mode of Excel. Possible values for this property are:

In this advanced chapter of OOP with Excel VBA, we implement objects composition with a dynamic collection in Excel VBA using Class Modules. Not for the faint of heart…

In Part 1 on this exercise of implementing OOP in Excel VBA, we left off with a half-baked order object. It had some properties and a couple of methods, but its line-items were missing.

Today we’re going to round up our order object to include its line-items.

Thinking about the right structure and arrangement of the line-items within the order object, two main characteristics should guide our thinking:

1. An order...

Ever wanted a concise, clear with code examples guide to implement OOP in Excel VBA? It is your lucky day. Read on…

After we covered in detail what OOP is in last week’s Blog post, we’re ready to see how this works in Excel VBA.

Keep your eyes on the Object

The key concept to keep in mind as we implement objects in Excel VBA, is that we are creating our own custom objects, on top of the available objects at our disposal out of the box.

The image here shows a list of the available properties and methods of the Workbook object.

This list is the exposed interface of the...

If we live in a world of objects and our computer programs help us manage our world, how about representing the world’s objects in our computer programs! * Object Oriented Programming explained

In order for you to understand this article, you need to know what an Object in computer programming is. Lucky for you, I just wrote about it last week.

Between Two Programming Paradigms

There are two dominating programming paradigms out there.

Procedural Programming

The basic concept is that of statements organized in modules and functions, executed in order.

Typically, there is a main...

Objects are a key element in computer programming. While objects are at center stage in Object Oriented Programming, they are widely used in procedural languages and serve as the building blocks of complete applications * Let’s understand objects!

What is an Object?

Simply put, an object is any “thing” you can actually see, physically.

For example, a person, a car, a pencil, a circle – are all physical objects.

Extending our perception of object to understand how objects are used in computer programming, an object can also offer a well-defined service: A Government...

Ever needed to run an Excel Macro every day automatically? I mean, without leaving Excel open or interacting with Excel at all. Here’s how you do this taking advantage of two technologies that comes with Windows

Why schedule a daily silent job?

In one of my customer’s project that manages trainings and certifications, employees receive email and SMS notifications on various events: upcoming training reminders, training result (with a certificate attached), change of instructor, training assessment reminders etc.

The technique for doing that is using a queue. All notifications...

Need your single Excel program to run on Windows and Mac? With Office 32-bit and Office 64-bit? You can do that using pre-compiler directives * Here’s what you need to know (and code!)

In my Blog post from last week In which I elaborated on writing VBA code that runs on both Office 32-bit and Office 64-bit, we ended up with a challenge. We need to include the PtrSafe and LongPtr qualifiers in external libraries declarations for Office 64-bit, but ignore these qualifiers in Office 32-bit environments (where they are unknown).

Today I’ll explain all about VBA’s pre-compiler...

Your Excel 2016 program runs perfect on your Excel 2016 32-bit, but fails on Excel 2007, or on Excel 2013 64-bit. Why that happens and how to write a fully compatible VBA program? Here are the answers (and some VBA code)

In last week’s Blog post, I explained and demonstrated how Windows functions libraries, or DLLs, can be called from VBA.

Leveraging external functions to Excel is great, especially considering the vast variety of functions the Windows operating system offers. However, breaking the tight Excel environment is also subject to some compatibility issues.

Why are there...

Windows offers tons of readily available functions that perform almost any task we need. Why not make use of it in our Excel VBA programs? * Here’s what you need to know about calling DLLs in Excel VBA

Modular Programming

As you recall from our computer programming lessons, one of the key concepts in good software design is modularity: breaking our code into functional subroutines or functions, each responsible for a specific task with a clear interface for calling it.

Once encapsulated in a self-contained function, this functionality can be re-used in many locations in your program....