In my last week’s Blog post I elaborated on data types and their use in VBA.
Beyond using the readily available native data types we’re all familiar with, such as Integer, Date, String and Boolean, we can define our own, user-defined data type.
Simply put, a user-defined data type is a group...
A data type is a structure to store data with given attributes and constraints.
You are probably familiar with some popular data types defined for us in VBA, such as an Integer, String and Date.
An Integer in VBA, for example, is allocated with 2 bytes to store numbers in the range -32,768 to 32,767.
A Date in VBA is allocated with 8 bytes to store numbers representing date and...
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....
Last week we introduced Enumerations and how they make our lives easier when handling numeric sets of constants.
Today we’ll take it further by exploiting the Enumeration data structure to handle combinations of values.
The typical use case we’re addressing here, is when we have to handle multiple-choice variables that can hold any...
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 last week’s Blog post I covered in great detail the Excel VBA MsgBox function. I will not repeat how user interaction is incredibly important, but as you now know how to present informative messages to your user, sometimes you also need some input from the user to feed your program.
As you probably know, you can employ VBA User Forms for highly...
Because this is where your program meets the psyche, mindset, values, thoughts and habits of the user. Can you guess what those are?
If the user doesn’t feel “at home” with your application, he would not want to use it. The American science fiction writer, Larry Niven, captured the importance of the user experience beautifully:
“That's the thing about people who think they hate...
Every color is identified by a unique number. For example, 255 represents Red. 16774980 represent a specific cyan.
You can also convert any decimal number to its Hexadecimal representation (or Hex for short). For example, that cyan color number equals FFF744 in Hex representation (use any decimal to hex converter you find on the web to see how it works).
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:
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.
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...