The GroupingCollection2 class lets you create grouped data from flat data
for display in the AdvancedDataGrid control.
When you create the instance of the GroupingCollection2 from your flat data,
you specify the field or fields of the data used to create the hierarchy.
Note: In the previous release of Flex, you used the GroupingCollection class
with the AdvancedDataGrid control.
The GroupingCollection2 class is new for Flex 4 and provides better performance
than GroupingCollection.
To populate the AdvancedDataGrid control with grouped data,
you create an instance of the GroupingCollection2 class from your flat data,
and then pass that GroupingCollection2 instance to the data provider
of the AdvancedDataGrid control.
To specify the grouping fields of your flat data,
you pass a Grouping instance to
the GroupingCollection2.grouping property.
The Grouping instance contains an Array of GroupingField instances,
one per grouping field.
The following example uses the GroupingCollection2 class to define
two grouping fields: Region and Territory.
Specifies the Grouping instance applied to the source data.
Setting the grouping property
does not automatically refresh the view,
so you must call the refresh() method
after setting this property.
Implementation public function get grouping():Grouping public function set grouping(value:Grouping):void
The source collection containing the flat data to be grouped.
If the source is not a collection, it will be auto-wrapped into a collection.
Implementation public function get source():Object public function set source(value:Object):void
summaries
property
public var summaries:Array
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 10, AIR 1.5
Array of SummaryRow instances that define any root-level data summaries.
Specify one or more SummaryRow instances to define the data summaries,
as the following example shows:
The timer which is associated with an asynchronous refresh operation.
You can use it to change the timing interval, pause the refresh,
or perform other actions.
The default value for the delay property of the
Timer instance is 1, corresponding to 1 millisecond.
Constructor Detail
GroupingCollection2
()
Constructor
public function GroupingCollection2()
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 10, AIR 1.5
Constructor.
Method Detail
cancelRefresh
()
method
public function cancelRefresh():void
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 10, AIR 1.5
If the refresh is performed asynchronously,
cancels the refresh operation and stops the building of the groups.
This method only cancels the refresh
if it is initiated by a call to the refresh() method
with an asynch argument of true, corresponding to an asynchronous refresh.
getParent
()
method
protected function getParent(node:Object):*
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 10, AIR 1.5
Returns the parent of a node.
The parent of a top-level node is null.
Parameters
node:Object — The Object that defines the node.
Returns
* — The parent node containing the node as child,
null for a top-level node,
and undefined if the parent cannot be determined.
getRoot
()
method
override public function getRoot():Object
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 10, AIR 1.5
Return super.source, if the grouping property is set,
and an ICollectionView instance that refers to super.source if not.
Returns
Object — The object to return.
refresh
()
method
public function refresh(async:Boolean = false, dispatchCollectionEvents:Boolean = false):Boolean
Language Version :
ActionScript 3.0
Product Version :
Flex 3
Runtime Versions :
Flash Player 10, AIR 1.5
Applies the grouping to the collection.
The collection does not detect changes to a group
automatically, so you must call the refresh()
method to update the collection after setting the grouping,
source, or summaries properties.
You also call the refresh() method when you modify
a GroupingField of the collection, such as by changing the
caseInsensitive, compareFunction,
or groupingFunction properties.
The refresh() method can be applied synchronously
or asynchronously.
When refresh() is called synchronously,
all groups and summaries are updated together before the method returns.
That means your application cannot perform other processing operations
for the duration of the call.
A client should wait for a CollectionEvent event
with the value of the kind property set
to CollectionEventKind.REFRESH
to ensure that the refresh() method completed.
In asynchronous refresh, all groups and summaries are updated individually.
The refresh() method returns before the groups and summaries
are updated so that your application can continue execution.
Also, the control is updated during the refresh so that the
user can continue to interact with it.
The overhead of updating groups and summaries individually,
rather than all at once, makes an asynchronous refresh take longer
than a synchronous one.
However, for large data sets, your application continues
to operate during the refresh.
Parameters
async:Boolean (default = false) — If true, defines the refresh to be asynchronous.
By default it is false denoting synchronous refresh.
dispatchCollectionEvents:Boolean (default = false) — If true, events are
dispatched when groups are formed.
For better performance, set it to false.
If true, then events are dispatched as groups and summaries are calculated
synchronously to update the control.
Note: If async is true,
the dispatchCollectionEvents is always set to true.
By default it is false denoting no events will be dispatched.
Returns
Boolean — true if the refresh() method completed,
and false if the refresh is incomplete,
which can mean that items are still pending.