by Add Komoncharoensiri, Director of Technical Services at 4D Inc
As you know, 4D Knowledge Base is a library of information about the 4D technology where weekly tech tips and monthly technotes are actively published. If you missed the last tips on the KB, that’s fine; here is a compilation from the past few weeks.
This blog post covers 12 tips:
List boxes are great, powerful tools to display data in the interface. They can display fields from records, items from arrays, and since recently, entity selections and collections.
While the new list boxes using collections or entity selections are more powerful in many ways, they did not allow time display and automatic calculations in their footers, unlike list boxes displaying arrays or records.
From now on, and as long as you use project mode, all types of list boxes can display hours in their columns, but also have the possibility to display calculations on their footers.
As a developer, you’re used to handling events inside form objects. The most common is the on clicked form event which can be used in most objects, including list boxes. In this particular object, clicks can be managed either at the list box level itself or within the column methods.
And starting with 4D v18 R6, the on clicked form event is triggered whether a cell is being edited or not, giving you increased control and improving the interface.
If you’re interested in the user interface, you may have already used the On before keystroke and On after keystroke events. You’ll certainly be happy to know that the handling of these events has been greatly enhanced with 4D v18 R5. In addition, a new command has been created to determine if there is ongoing input when the On before keystroke event is generated. Let’s find out more!
Interested in building list boxes that can automatically adapt the height of each row to its content so that the full text or picture can be displayed? What about using object arrays in columns (this allows entering and displaying various types of values in the rows of a single list box’s column).
These are very cool features, right? Previously, you needed to have a valid 4D View Pro license in order to use them. Well, not anymore!
4D v18 R4 lets you access these features for FREE! No additional licensing is required, they’re now included in the standard product.
List boxes are powerful form objects. They’re easily created and manipulated, and most importantly, they can handle any kind of data. Additionally, they can be fully set up by programming … everything from inserting or deleting rows and columns, to defining or modifying tons of properties using the 4D language. With 4D v18 R4, another important property has been added to the list. Can you guess which one? Hint: read the title again.
To display a list of records, an entity selection list box is the most suitable when using ORDA technology. 4D v18 R2 simplifies your life with a new tool to easily build entity selection list boxes: List box builder. What is it? It’s a simple dialog where you can set up your list box in a few quick steps (select the table and fields to display, enter column titles, and define the column order).
by guest author Chris Belanger, a 4D developer from Canada
List box typeahead (a method for progressively searching) is not a native feature of list boxes. However, you can easily implement this feature with some creative coding. In this blog post, I’ll demonstrate the technique along with a database example and an exhaustive document explaining the details step by step.
The final result is summarized in the GIF below, It illustrates two “searches”. One for E-L-L-I-O-T, then another (after a column sort) for H-A-N-N-A-H: