Pakiet | mx.controls.listClasses |
Interfejs | public interface IDropInListItemRenderer |
Implementory | AdvancedDataGridGroupItemRenderer, AdvancedDataGridHeaderRenderer, AdvancedDataGridItemRenderer, AdvancedListBase, Button, ComboBox, DataGridItemRenderer, DateField, FTEAdvancedDataGridItemRenderer, FTEDataGridItemRenderer, HTML, Image, Label, ListBase, ListItemRenderer, MXAdvancedDataGridItemRenderer, MXItemRenderer, MenuItemRenderer, NumericStepper, OLAPDataGridGroupRenderer, RendererBase, TextArea, TileListItemRenderer, TreeItemRenderer |
Wersja języka: | ActionScript 3.0 |
Wersja produktu: | Flex 3 |
Wersje środowiska wykonawczego: | Flash Player 9, AIR 1.1 |
text
property. This
is easy to write using data-binding, but has the negative
consequence that the renderer cannot be re-used in another column
of a DataGrid or another List with different fields.
IDropInListItemRenderer allows a renderer to be re-used. The list
classes will pass more information to the renderer so that it
can determine which field to use at run-time.
Components that you want to use as drop-in item renderers or drop-in item editors must implement the IDropInListItemRenderer interface. Many Flex component implement this interface, and therefore are usable as drop-in item renderers and drop-in item editors in any column or list.
Drop-in item renderers or drop-in item editors also must implement
the IDataRenderer interface to define the data
property.
When a component is used as a drop-in item renderer or drop-in
item editor, Flex initializes the listData
property
of the component with the appropriate data from the list control.
The component can then use the listData
property
to initialize the data
property of the drop-in
item renderer or drop-in item editor.
The listData
property is of type BaseListData,
where the BaseListData class has four subclasses:
DataGridListData, ListData, TreeListData, and MenuListData.
The actual data type of the value of the listData
property
depends on the control using the drop-in item renderer or item editor.
For a DataGrid control, the value is of type DataGridListData,
for a List control the value is of type ListData,
for a Tree control, the value is of type TreeListData,
and for a Menu control, the value is of type MenuListData..
The following example shows the setter method for the
data
property for the NumericStepper control
that initializes NumericStepper's value
property
based on the value of the listData
property:
public function set data(value:Object):void { _data = value; this.value = _listData ? parseFloat(_listData.label) : Number(_data); dispatchEvent(new FlexEvent(FlexEvent.DATA_CHANGE)); }
In the example above, the NumericStepper control ignores the
data
property when setting NumericStepper's
value
property, and uses the listData
property instead.
To implement the IDropInListItemRenderer interface,
you define a setter and getter method to implement
the listData
property.
Typically, the setter method writes the value of the
listData
property to an internal variable.
The list class always assigns this property then sets
the data provider item in the data
property.
Notice that the setter method for the listData
property
does not dispatch an event.
This is because the list classes always set listData
,
then set the data
property.
Setting the data
property also dispatches the dataChange
event.
You never set listData
on its own,
so it does not need to dispatch its own event.
The data
setter method could call the invalidateProperties()
method
if it did something that required the control to update itself.
It would then be up to the component developer to write a commitProperties()
method
to determine that listData
was modified, and handle it accordingly.
The getter method returns the current value of the internal variable, as the following example shows:
// Internal variable for the property value. private var _listData:BaseListData; // Make the listData property bindable. [Bindable("dataChange")] // Define the getter method. public function get listData():BaseListData { return _listData; } // Define the setter method, public function set listData(value:BaseListData):void { _listData = value; }
Powiązane elementy interfejsu API
Właściwość | Zdefiniowane przez | ||
---|---|---|---|
listData : BaseListData
Implements the listData property
using setter and getter methods. | IDropInListItemRenderer |
listData | właściwość |
listData:BaseListData
Wersja języka: | ActionScript 3.0 |
Wersja produktu: | Flex 3 |
Wersje środowiska wykonawczego: | Flash Player 9, AIR 1.1 |
Implements the listData
property
using setter and getter methods.
Implementacja
public function get listData():BaseListData
public function set listData(value:BaseListData):void
Tue Jun 12 2018, 12:06 PM Z