SWhile the HyperCube is the main object for calculating data the ListboxObject is a way to list available values for a field. Its the object behind the listboxes in the Filter Panel. It is also the object used for the listboxes that are created when you click on a field in the selection toolbar.
An example setup from the horizontal listbox extension example, included with the Qlik Sense installation:
This contains defaults for most of the parameters, except the actual field, which the user selects in the property panel, which looks like this:
As you can see the Listbox has either a predefined measure from the library, in which case qListObjectDef.qLibraryId will contain the id of the measure (some UID string) or it has a field name, which will be in the array qListObjectDef.qDef.qFieldDefs at the first position. You don’t really have to bother about which one the user selects to use, the ListboxObject will work the same anyhow.
Frequencies and sort order
There are also some other properties in the ListboxObject that are well known to QlikView users. The frequence mode gives you some additional info on the frequency of the respective values in the ListboxObject. Look to horizontal listbox extension for an example. There is also the qSortCriterias array, which allows you to specify the sort order. The default is to have the selected values first, but you might want to for example keep months order from January to December irrespective of which month is selected.
Mashup editor – even more properties
Like with the Hypercube, you can also build a ListboxObject in the mashup editor. The tool to do this looks like this:
As you can see, you also get the option to include expressions in your listbox, usable if you want to make some calculations for each value in the list. The mashup editor will create a ListboxObject for you like this:
The expressions are added to the ListboxObject in the qExpressions array. In this example I have used predefined measures, but you can also use measures defined in the actual listbox object. The mashup editor includes a expression editor (actually the same used in the Qlik Sense client) to help you with this.