我们希望在数据网格中有一个允许多选的复选框。我们扩展了DataGrid对象：
package obj
{
import mx.controls.DataGrid;
import flash.display.Sprite;
import flash.events.KeyboardEvent;
import mx.controls.CheckBox;
import mx.controls.listClasses.IListItemRenderer;
public class CheckboxDataGrid extends DataGrid
{
override protected function selectItem(item:IListItemRenderer,
shiftKey:Boolean, ctrlKey:Boolean,
transition:Boolean = true):Boolean
{
// only run selection code if a checkbox was hit and always
// pretend we're using ctrl selection
if (item is CheckBox)
return super.selectItem(item, false, true, transition);
return false;
}
// turn off selection indicator
override protected function drawSelectionIndicator(
indicator:Sprite, x:Number, y:Number,
width:Number, height:Number, color:uint,
itemRenderer:IListItemRenderer):void
{
}
// whenever we draw the renderer, make sure we re-eval the checked state
override protected function drawItem(item:IListItemRenderer,
selected:Boolean = false,
highlighted:Boolean = false,
caret:Boolean = false,
transition:Boolean = false):void
{
CheckBox(item).invalidateProperties();
super.drawItem(item, selected, highlighted, caret, transition);
}
// fake all keyboard interaction as if it had the ctrl key down
override protected function keyDownHandler(event:KeyboardEvent):void
{
// this is technically illegal, but works
event.ctrlKey = true;
event.shiftKey = false;
super.keyDownHandler(event);
}
}
}
我们还创建了一个CheckboxRenderer：
package obj
{
import flash.display.DisplayObject;
import flash.events.KeyboardEvent;
import flash.events.MouseEvent;
import flash.text.TextField
import mx.controls.CheckBox;
import mx.controls.dataGridClasses.DataGridListData;
import mx.controls.listClasses.ListBase
public class CheckBoxRenderer extends CheckBox
{
public function CheckBoxRenderer()
{
focusEnabled = false;
}
override public function set data(value:Object):void
{
super.data = value;
invalidateProperties();
}
override protected function commitProperties():void
{
super.commitProperties();
if (owner is ListBase)
selected = ListBase(owner).isItemSelected(data);
}
/* eat keyboard events, the underlying list will handle them */
override protected function keyDownHandler(event:KeyboardEvent):void
{
}
/* eat keyboard events, the underlying list will handle them */
override protected function keyUpHandler(event:KeyboardEvent):void
{
}
/* eat mouse events, the underlying list will handle them */
override protected function clickHandler(event:MouseEvent):void
{
}
/* center the checkbox if we're in a datagrid */
override protected function updateDisplayList(w:Number, h:Number):void
{
super.updateDisplayList(w, h);
if (listData is DataGridListData)
{
var n:int = numChildren;
for (var i:int = 0; i < n; i++)
{
var c:DisplayObject = getChildAt(i);
if (!(c is TextField))
{
c.x = (w - c.width)/2;
c.y = 0;
}
}
}
}
}
}
然后在您的Flash页面：
<obj:CheckboxDataGrid id="notificationsCheckboxGrid"
dataProvider="{_myModel._grid}"
allowMultipleSelection="true"
showHeaders="false"
change="emailAddressesSelected()">
<qmsAdmin:columns>
<mx:DataGridColumn width="20" sortable="false" itemRenderer="CheckBoxRenderer"/>
<mx:DataGridColumn width="150" dataField="email"/>
<mx:DataGridColumn dataField="notificationType"/>
</qmsAdmin:columns>
</obj:CheckboxDataGrid>
通知改变方法 “emailAddressesSelected（）”。调用此方法：
private function emailAddressesSelected():void
{
_emailAddressIndexesSelected = notificationsCheckboxGrid.selectedIndices;
}
_emailAddressIndexesSelected是被定义为在类只是一个Array对象：
private var _emailAddressIndexesSelected:Array;