DropDownByIndex  

The Web Dynpro class DropDownByIndex , which implements the IWDDropDownByIndex interface, is the base class of the dropdown list boxes for which index binding is used.

Definition

A DropDownByIndex UI element provides the user with a dropdown list box. You cannot select more than one entry from the selection list. The UI element consists of a text field, a button, and a selection list. Any list entry already selected is displayed in the text field. When selecting the button, a list with all possible values is displayed.

Visual Display:

When using a dropdown list box, always display this UI element alongside a label to ensure accessibility.

Description of UI Element Properties

●      explanation

specifies the explanation text. explanation is maintained by the documentation developer in the Web Dynpro Authoring environment.

●      labelFor

The DropDownByIndex element can also be used as a label for other UI elements. You can use the labelFor property to reference to a UI element.

●      readOnly

specifies whether the user can select an element.

●      selectionChangeBehaviour

The change of the lead selection can cause a data loss – for example, if the changed or new data was not written to the context due to syntax errors. You can avoid the data loss using the selectionChangeBehaviour property before changing the lead selection:

auto	If the data was written to the context, the value auto specifies that the DropDownByIndex automatically changes the lead selection of its data source directly after an interaction by the user before the corresponding event is triggered.
manual	Specifies that the DropDownByIndex does not change the lead selection of its data source after an interaction by the user but triggers the corresponding event. In this case, the event handler must change the lead selection to enable the DropDownByIndex to display the data in a main detail view, for example. This setting allows you to check the change of the lead selection.

●      size

This property is deprecated and can no longer be used.

●      state

displays the status of the DropDownByIndex. The stateproperty can take the following values and is represented by enumeration type WDState.

○       normal

○       required. The required state will be displayed by an asterisk.

●      textDirection

Specifies the text direction. This enables the labels for the DropDownByIndex to be read in other languages that require a specific text direction. The textDirection property can take the following values and is represented by enumeration type WDTextDirection.

inherit	The text direction is inherited from the parent element. The text direction is thus identical to that of the parent element.
ltr	The text runs from left to right.
rtl	The text runs from right to left.

The default value for this property is inherit.

●      texts

Specifies the path to the context attribute that provides the texts for the DropDownByIndex. The context attribute must be an attribute of a multiple context node which stores the data.

●      width

Determines the width of the DropDownByIndex. You can specify this in CSS sizes, such as em, ex, pixels or percentage values.

Properties Overview

Name	Interface	Type	Initial Value	Bindable
enabled	IWDUIElement	boolean	true	bindable
explanation	IWDDropDownByIndex	String		not_bindable
labelFor	IWDAbstractDropDown	String		not_bindable
readOnly	IWDAbstractDropDown	boolean	false	bindable
selectionChangeBehaviour	IWDAbstractDropDownByIndex	WDLeadSelectionChangeBehaviour	auto	not_bindable
state	IWDAbstractDropDown	WDState	normal	bindable
textDirection	IWDAbstractDropDown	WDTextDirection	inherit	bindable
texts	IWDAbstractDropDownByIndex	String		bindable_mandatory
tooltip	IWDUIElement	String (TranslatableText)		bindable
visible	IWDUIElement	WDVisibility	visible	bindable
width	IWDAbstractDropDown	String		bindable

Events

●      onSelect

This event is triggered when the user selects a different list entry from the dropdown box.
The newly selected index (starting from zero) is passed as an event parameter.

Event Parameter	Type	Description
index	int	Index of the newly selected context element

 

Data Binding

For further information, refer to Data Binding of a Dropdown List Box and Radio Button Group and Code Examples for Data Binding.