I have a list that accepts drops. When an item is dropped (DragEvent.DRAG_DROP) I need to collect the data that is dropped, however I have found nothing in the event that helps me do so, event.dragInitiator.selectedItems would work but gives me an error.
Any help would be appreciated.
The data should be in event.dragSource. You'll have to check for the proper format using hasFormat() and retrieve it with dataForFormat(). Here are the docs for DragSource.
Code would be something like this (assuming this is Flex 4):
// In dragDrop handler or dragComplete
if (event.dragSource.hasFormat("itemsByIndex"))
{
var items:Vector.<Object> = event.dragSource.dataForFormat("itemsByIndex") as Vector.<Object>;
// Do stuff with items
}
You can also listen to changing dataProvider.
list.dataProvider.addEventListener(CollectionEvent.COLLECTION_CHANGE, list_dataProvider_change);
...
protected function list_dataProvider_change(e :CollectionEvent) :void
{
if (e.kind == CollectionEventKind.REMOVE)
trace('list element removed from - index', e.location);
else if (e.kind == CollectionEventKind.ADD)
trace('list element added to - index', e.location);
}
Related
Im working on a piece of code using DevExpress XAF, I noticed that if im using the event OnSaving that the code executes 2 times, how can i prevent that
protected override void OnSaving()
{
if (PrestamoP != null)
{
PrestamoP.Prestado -= Monto;
PrestamoP.Save();
}
else if (PrestamoG != null)
{
PrestamoG.Prestado -= Monto;
PrestamoG.Save();
}
base.OnSaving();
}
XPO does not guarantee that the OnSaving method is called once. See the corresponding note in the XPO Best Practices article.
I can see that you are changing the PrestamoP.Prestado property based on the value of the Monto property. This code is fine if you execute it only once and only when the Monto property is specified for the first time. This code is not fine if you:
Save this object without changing the Monto property;
Update the early specified Monto value.
So, it appears that a more complex logic is required for the PrestamoG.Prestado property. First, I would move it to the Monto property setter and take the previous value into account (do not forget to check the IsLoading property in this case). Second, I would consider calculating the Prestado value dynamically instead of storing its value. This will allow you to resolve issues with the duplicate business logic execution. See an example here: How to: Calculate a Property Value Based on Values from a Detail Collection.
I can offer different methods for CRUD functions on onSaving method.
IsNewObject, IsDeleted.
// insert
if (Session.IsNewObject(this))
{
a = new a(Session);
a.CreateReferencedProperties(this);
}
// delete
else if (IsDeleted)
{
a= Session.FindObject<A>(PersistentCriteriaEvaluationBehavior.InTransaction, CriteriaOperator.Parse("A=?", this));
if (a!= null)
a.Delete();
}
// update
else
{
a= Session.FindObject<A>(PersistentCriteriaEvaluationBehavior.InTransaction, CriteriaOperator.Parse("A=?", this));
if (a!= null)
a.CreateReferencedProperties(this);
}
You can use the code below to prevent xaf from entering on saving twice.
base.OnSaving();
SessionObjectLayer sessionObjectLayer = this.Session.ObjectLayer as SessionObjectLayer;
if (sessionObjectLayer == null || sessionObjectLayer.ParentSession == null)
{
//Enter only once
}
I'm using a View Based NSTableView and binding to display content of my objects.
When I delete one of them, the tableView reflect the change, by removing the cell for this object.
The problem is that the NSTableCellView doesn't receive the setObjectValue: with nil or another object, and so the object referenceCount is not decremented, and my object never release.
Is there a way to override the tableView to force calling setObjectValue: when it cache deletedRows?
Thanks for your help.
I just found the solution right here.
https://devforums.apple.com/message/575883#575883
Just in case the link fail, the solution is to set it manually, in the following method
- (void)tableView:(NSTableView *)tableView didRemoveRowView:(NSTableRowView *)rowView forRow:(NSInteger)row NS_AVAILABLE_MAC(10_7);
{
for (NSInteger columnIndex = 0; columnIndex < [rowView numberOfColumns]; columnIndex++) {
[[rowView viewAtColumn:columnIndex] setObjectValue:nil];
}
}
I have a spark List defined as:
<s:List id="symbolList" dataProvider="{symbolListCollection}" change="symbolNameChangeHandler(event)"></s:List>
With the change handler defined like this:
protected function symbolNameChangeHandler(event:IndexChangeEvent):void {
symbolList.validateProperties();
changeSymbolView(symbolList.selectedItem);
}
and symbolListCollection as an ArrayList filled with Strings.
At first, the change event works fine, and I get what I expect.
However, if I Ctrl-click on the selected item, to de-select it, i am unable to ever select an item again.
When I click on something to try to select it, the change event DOES fire, however, the ItemChangeEvent has both oldIndex and newIndex set to -1
Any idea what I might have done to cause this, or what I can do to remedy it?
OK found my own issue.
In the method changeSymbolView(), I had the following line:
if(selectedItem == null) {
symbolList.selectedItem = null;
}
Somehow, this line prevented it from ever being selectable again. Removing it caused it to work as expected.
I have a DropdownList that shows a list of providers & the Provider associated with that Patient must be selected.
The Dropdown list:
<s:DropDownList id="providerList"
width="80%"
fontSize="12"
fontWeight="bold"
selectionColor="white"
creationComplete="providerList_creationCompleteHandler(event)"
dataProvider="{model.practiceProviderList.practiceProviders}"/>
where practiceProviders is an ArrayCollection
The CreationCompleteHandler function:
protected function providerList_creationCompleteHandler(event:FlexEvent):void
{
var firstN:String;
var lastN:String;
var providerObj:Provider = new Provider();
if (model.patientDetails.patientDetail.patientProviders != null && model.patientDetails.patientDetail.patientProviders.length > 0)
{
firstN = patientDetailsModel.patientDetails.patientDetail.patientProviders.getItemAt(0).provider.providerName.firstName;
lastN = patientDetailsModel.patientDetails.patientDetail.patientProviders.getItemAt(0).provider.providerName.lastName;
for (var count:int = 0; count < patientDetailsModel.practiceProviderList.practiceProviders.length; ++count)
{
providerObj = patientDetailsModel.practiceProviderList.practiceProviders.getItemAt(count, 0).provider as Provider;
if (providerObj.providerName.firstName == firstN && providerObj.providerName.lastName == lastN)
{
this.providerList.selectedIndex = count;
}
}
}
}
The issue is when I go to this page the first time, the error is :
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at com.newwavetechnologies.modules::demographics/providerList_creationCompleteHandler()[C:\harish\flex\apps\workspace\dataCollection-flexUserInterface\src\com\newwavetechnologies\modules\demographics.mxml:166]
at com.newwavetechnologies.modules::demographics/__providerList_creationComplete()[C:\harish\flex\apps\workspace\dataCollection-flexUserInterface\src\com\newwavetechnologies\modules\demographics.mxml:359]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.core::UIComponent/dispatchEvent()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\core\UIComponent.as:12266]
at mx.core::UIComponent/set initialized()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\core\UIComponent.as:1577]
at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\managers\LayoutManager.as:759]
at mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\managers\LayoutManager.as:1072]
where line 166 is:
if (providerObj.providerName.firstName == firstN && providerObj.providerName.lastName == lastN)
The providerObj is null the first time. But when hit back and come to the same page again, everything works fine and 1 of the providers in the list is selected correctly.
Probably I think the first time, the creationComplete handler method is called before the List is populated. The 2nd time when the call is made, the list is populated and the handler works fine. It would be great if someone can help me in this regard on how to go about this.
Thanks
Harish
It's hard to tell what's going on here, but the problem lies here:
providerObj = patientDetailsModel.practiceProviderList.practiceProviders.getItemAt(count, 0).provider as Provider;
There's a tonne of places in that line that Null pointer exceptions could occur.
Most likely - the practiceProvider returned at position count doesn't have a provider set. We can't see how this value is populated, but given this code works later, I'd say you've got a race condition happening - the data is being accessed before it's been set.
At very least, you should add a guardClause for this:
var practiceProviders:ArrayCollection = patientDetailsModel.practiceProviderList.practiceProviders;
for (var count:int = 0; count < practiceProviders.length; ++count)
{
providerObj = practiceProviders.getItemAt(count, 0).provider as Provider;
if (!providerObj)
continue;
// etc
}
The race condition is a little trickier, given the asyncronous natoure of flex server calls. (I'm assuming that you're loading the data from a remote server).
There's two approaches to solve this - either
defer execution of this method until the data has loaded - you could do this by adding an eventListener to the ResultEvent of the RemoteService
or
Don't worry about it the first time around, but re-execute the method whenever the data changes.
eg:
protected function providerList_creationCompleteHandler(event:FlexEvent):void
{
dataProvider.addEventListener(CollectionEvent.COLLECTION_CHANGE,onCollectionChange,false,0,true);
updateProviders();
// Rest of existing creationComplete code moved to updateProviders();
}
private function updateProviders()
{
// Code from existing creationComplete handler goes here
}
private function onCollectionChange(event:CollectionEvent):void
{
updateProviders();
}
I have item renderers in an mx.controls.Tree that I need to refresh on demand.
I have code in the updateDisplayList that fires for only some of the visible nodes no matter what I do. I've tried triggering a change that they should all be listening for; I have tried clearing and resetting the dataProvider and the itemRenderer properties.
private function forceCategoryTreeRefresh(event : Event = null) : void
{
trace("forceCategoryTreeRefresh");
var prevDataProvider : Object = CategoryTree.dataProvider;
CategoryTree.dataProvider = null;
CategoryTree.validateNow();
CategoryTree.dataProvider = prevDataProvider;
var prevItemRenderer : IFactory = CategoryTree.itemRenderer;
CategoryTree.itemRenderer = null;
CategoryTree.itemRenderer = prevItemRenderer as IFactory;
_categoriesChangeDispatcher.dispatchEvent(new Event(Event.CHANGE));
}
The nodes refresh properly when I scroll them into view (e.g. the .data gets set), but I cannot force the ones that already exist to refresh or reset themselves.
Any ideas?
Try calling this function on change event:
private function refreshList(e:Event):void{
listName.invalidateSize();
listName.invalidateList();
listName.invalidateDisplayList();
listName.validateSize(true);
listName.validateNow();
}
for me work quite well
Try
treeView.dataProvider = treeView.dataProvider;
That should update Tree view.
ItemRenderers in Flex are virtualized so there will not always be one ItemRenderer for each Tree node.
However, you can invalidate the nodes to force a refresh. The answer to this question gives an example of how to do that.