Multiselect combobox
A multiselect combobox resembles a Combobox, but allows the selection of multiple options listed in a dropdown.
Selected elements are represented by a set of labels in the title row of the element:
Adding individual options to the selection is possible by one of the following methods:
Click an entry listed in the dropdown
Enter a search string in the title row (unless search is deactivated) and confirm a result – identified by cursor keys (up/down) if required – with 'Enter'
For removing the options from the current selection the following methods are supported:
Click the 'X' symbol in the label representing the option in the title row
Press 'Del' key (Delete), after focussing the respective label in the title row (grey background color)
Click the respective entry in the dropdown list, which appears grey for selected elements
Besides, the selection menu at the bottom edge of the dropdown area features Convenience selectors described below, for multi-option operations.
Entries and services
Most configuration settings in section 'Entries and services' are featured as described for Combobox – with the following exceptions:
Options Min. values and Max. values define restrictions for the number of options to select (a value of 0 defines 'unrestricted').
Option 'Allow empty selection' is omitted, since setting Min. values to a value > 0 has the same effect.
Convenience selectors
In contrast to the simple Combobox element, the dropdown area of a multiselect combobox features a selection menu with the following convenience selectors for (de)selecting multiple options:
|
Selector operation |
Description |
|
all |
All available options from the dropdown are added to the selection. |
|
inverse |
The current selection is inverted: Currently selected options are deselected, available options that are currently deselected are added to the selection. |
|
none |
All options are removed from the current selection. |
►IMPORTANT◄ The service configured for a multiselect combobox may not always present all effectively available options in the dropdown list, but might extend the scope of featured options step by step when a user scrolls down ('Paging'). In this case, operators 'all' and 'inverse' will only add options to the list, that are currently presented in the dropdown. Some services feature a configuration parameter 'Max. results', to control how many entries are loaded at a time. A value of 0 defines all options are loaded at once, which may cause performance issues within a form.
View type 'Options'
As for a Combobox the multiselect combobox features a View type setting 'Options' in the section Common, which all available options visible at once and eligible by checkboxes in the form.
Specific configurations settings for view type 'Options' are available in the section Option elements:
The option Align vertical arranges all options vertically (like items of a list).
With this option deselected (default), options are arranged horizontally (like words in a sentence). In this case, the option Options can wrap decides if the sequence of options will populate several "rows", in case horizontal space for the surrounding container is limited.
The option Display option labels controls whether (default) or not labels are indicated next to each checkbox.
View type 'Selection list'
In addition to the view types available for Combobox, multiselect comboboxes feature a View type 'Selection list', which lines up Included vlaues and Excluded values as items of a set of list elements with a search/filter function. In this combination clicking an option moves it to the opposite list.
As shown in the screenshot, the element for Excluded items features the selection menu with the convenience selectors for (de-)selecting sets of elements.
►NOTE◄ Strings entered into the search field (with the looking glass symbol) are interpreted as filter criteria, so options that are (de) selected may seem to disappear, if the do not match the filter set for the target list.