Web Dynpro AbstractDropDownByIndex API - IWDAbstractDropDownByIndex 

Definition

The AbstractDropDownByIndex class which implements the IWDAbstractDropDownByIndex interface is the abstract base class of a dropdown list box that uses the Index Binding Model for data binding.

The view context provides the content to be displayed in the dropdown list box and the selected index.

The view context must contain a context node X that can store any number of node elements (X.cardinality=0..n). Each node element represents an entry in the the dropdown list box.

The context node X contains a context attribute y that provides the texts for the list entries. The data type of the context attribute y can be any simple data type – for example, String, int, and so on. If the data type of the context attribute y is not of the type String, this type is converted into a String representation by the Web Dynpro Framework. The selected value is specified by the lead selection of the node X.

The texts property of the DropDownByIndex UI element is bound to the attribute y by assigning the path of the context X.y to the texts property.

Example for Data Binding of the DropDownByIndex UI Element:

Procedure at design time:

...

       1.      Create a view with the name TestView.

       2.      Insert the DropDownByIndex UI element as a container child of the TestView view (step 1).

       3.      Create the context structure, as described in step 2.
Create the context node X with the cardinality 0..n. Insert the value attribute y of the type String into this node. This is followed by the data binding of the DropDownByIndex UI element in the Properties window of the View Designer. The texts property must be bound to the value attribute y with the context path describtion TestView.X.y (step 3).
The context path TestView.X.y describes the attribute y in the context node X of the view context of the TestView view.

You can fill the context with test data using the following controller implementation.

public void wdDoInit()   {     //@@begin wdDoInit()    String[] letters = new String []    {"A", "B", "C", "D"};   //Create context elements for the node "X"    List nodeElements = new ArrayList();    for (int i =  0; i <letters.length; ++i)    {       IPrivateTestView.IXElement xElement = wdContext.createXElement();       xElement.setY(letters[i]);       nodeElements.add(xElement);    }   //Bind node element list to the node    wdContext.nodeX().bind(nodeElements);   //Set node’s lead selection which determines the selected item    wdContext.nodeX().setLeadSelection(1);       //@@end   }

Behavior at runtime:

At runtime, a context node consists of a number of node elements, which contain the values to be displayed – as schematically illustrated in step 4. The lead selection is set to the second value (zero-based index). Step 5 shows the dropdown list box with the possible values A, B, C, and D, as it is displayed in the browser.

Description of the UI Element Property

·         texts
Determines the content of the list entries.

Overview of Inherited and Additional Properties

Name	Interface	Type	Initial Value	Bindable	Value Required
enabled	IWDUIElement	boolean	true	bindable	No
readOnly	IWDAbstractDropDown	boolean	false	bindable	No
state	IWDAbstractDropDown	WDState	normal	bindable	No
texts	IWDAbstractDropDownByIndex	String		bindable_mandatory	Yes
tooltip	IWDUIElement	String (TranslatableText)		bindable	No
visible	IWDUIElement	WDVisibility	visible	bindable	No
width	IWDAbstractDropDown	String		bindable	No

Events

·         onSelect
This property can assign the action to be executed when the user selects a different list entry from the dropdown list box. The newly selected index (starting from zero) is passed as the event parameter t.

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

See Parameter Mapping.

Subordinated Interfaces

IWDDropDownByIndex.

Methods in the Web Dynpro IWDAbstractDropDownByIndex API

Method Name	Parameter	Return Value	Short Description
bindingOfTexts		String	Returns the path of the context element to which the texts property is bound. Returns NULL if no binding exists.
bindTexts	(String path)		Binds the texts property to the context node specified by a path.
getOnSelect		IWDAction	Returns the action that is executed when the onSelect event is triggered.
mappingOfOnSelect		IWDParameterMapping	Returns the parameter mapping for the onSelect action.
setOnSelect	(IWDAction action)		Sets the action that is executed when the onSelect event is triggered.

Additional methods described in the following APIs are available using inheritance: IWDAbstractDropDown, IWDUIElement, IWDViewElement.

For further information about all inherited methods, refer to the documentation for the relevant APIs.