I am new to Flex and want to programmatically determine the value selected from a MultiSelectComboBox. The code is as follows:
<columns: ExtendedDataGridColumn
width="50" dataField="department"
filterComboBoxBuildFromGrid="false"
filterComboBoxDataField="label"
filterComboBoxDataProvider="{deptCollection}"
filterControl="MultiSelectComboBox"
filterOperation="Equals"
sortable="true" />
Whenever you need to check the selected value (or values), use the selectedItems property:
private function querySelections() {
foreach (var item:* in multiComboBox) {
trace(item.id);
}
}
Of course, you'll need to make sure that you can get a reference to the MultiSelectComboBox to the code that wants to read it. If it's defined inside an ItemRenderer, you'll need to make sure to expose it to the calling code.
Related
I am using view stack...so when view change like when we move from one page to another hide event is dispatched.So i am saving the information of last page in hide event before i go to next page.but thing is that if i change nothing still change on view hide event is invoked nd call go to backend...i just want do call only if sumthing change in the view..like sum text value...So i have two options
use event listener on each component if sumthing change its make the flag true...nd hide event check, if flag is true send call to backend.
event listener at container level ..if sumthing change in child componenet through bubbling container knows if sum event is dispatched.nd makes the flag true.
I have doubt with container...
Can i use container, and how?
Reason why I can't use container?
What are the pros and cons either way?
I would recommend using a dataProvider with the ability to compare them. For instance, if you are changing things with textinputs, you could basically do something like this:
[Bindable]
private var myDataProvider:Object = new Object();
private function creationCompleteHandler():void {
myDataProvider.updated = false;
myDataProvider.defaultValue = 'default';
myDataProvider.defaultValueTwo = 'default';
}
etc.
Then, in your mxml, you can have something like this:
<mx:TextInput id="myText" text="{myDataProvider.defaultValue}" change="myDataProvider.defaultValue=myText.text; myDataProvider.updated=true;" />
Lastly, in your hide event, you can do the following:
private function hideEventHandler( event:Event ):void {
if( myDataProvider.updated ){
// Call your RemoteServices (or w/e) to update the information
}
}
This way, when anything changes, you can update your dataProvider and have access to the new information each time.
Hope this helps!
I've used an approach similar to your first option in a couple of my past projects. In the change event for each of my form's controls I make a call to a small function that just sets a changesMade flag to true in my model. When the user tries to navigate away from my form, I check the changesMade flag to see if I need to save the info.
Data models are your friend!
If you get in the habit of creating strongly typed data models out of your loaded data, questions like this become very basic.
I always have a key binding set to generate a code snipit similar to this...
private var _foo:String;
public function get foo():String
{
return _foo;
}
public function set foo(value:String):void
{
if(_foo == value)
return;
var oldVal:String = _foo;
_foo = value;
this.invalidateProperty("foo", oldVal, value);
}
If your data used getters/setters like this, it would be very easy to validate a change on the model level, cutting the view out of the process entirely.
This seems like something that should be painfully simple, but I can't even find how to loop through rows in a Flex DataGrid.
Basically what I'm trying to accomplish is something like this pseudo-code:
for each(var row:Row in myDataGrid.Rows)
{
if(row.DataObject.Number == 1)
{
row.Color = Red;
}
}
I'm trying to have a Save button that upon being clicked either processes the save, or highlights the invalid rows and pops up a message telling the user why the rows are invalid. Because of some other complexities, I am not able to validate each row as it is entered. Any help is appreciated! Thanks.
Data grids are intended to be driven by their data rather than manipulated directly. One way to accomplish what you are trying to do is to add some sort of property, say "valid", to the data objects in your provider and add code to the renderer to alter its appearance based on the state of "valid". In that way you could loop through the objects in your data provider and set the "valid" property based on your validation check, which would cause the rows in the data grid to change their appearance automatically.
Hope that helps.
Try something like this:
for each(var o:Object in myDataGrid.dataProvider)
{
if(o.Number == 1) {
myDataGrid.selectedItems.push(o);
}
}
In your mxml you can set the selectionColor of the datagrid to red. See: http://blog.flexexamples.com/2008/02/19/setting-the-selection-color-and-selection-disabled-color-for-a-row-in-the-flex-datagrid-control/
Let me know if this works for you!
I am not sure you can do it on the data grid itself, but if you have an item renderer for each of the items, you can have your highlighting logic there.
basically, you define your datagrid's item renderer class:
<mx:DataGrid itemRenderer="ItemRendererClass"(...) ></mx:DataGrid>
and then you define the class "ItemRendererClass" as implementing IDataRenderer:
implements="mx.core.IDataRenderer"
This is a simplistic explanation, assuming you can figure out how to do this on yourself :)
I achieved this by overriding the set data. I have provided the sample code below.
override public function set data(value:Object):void
{
super.data=value;
if(value!=null && value.hasOwnProperty("state") && value.state == "Final State"){
setStyle("color", 0xb7babc);
}else{
setStyle("color", 0x000000);
}
this.selectable=false;
super.invalidateDisplayList();
}
I have a spark List control. It has a dataProvider that shows reply from twitter search.
I have created a function for change handler like this:
protected function list_changeHandler(event:IndexChangeEvent):void
{
ta.text = coverflow.selectedItem.title;
}
So, whenever I select each of the items in the List, I will see the message(ta.text)
but now, instead of me manually clicking the first time, I want it to automatically click/select the first item and see the first message(ta.text)
How can I achieve this?
You should set the requireSelection property to true on the list control
<s:List id="myList" dataProvider="{myDataProvider}" requireSelection="true"/>
How about to try this solution? :)
Your list control also has event name creationComplete (similar to change event). Try to select your first item with this:
protected function list1_creationCompleteHandler(event:FlexEvent):void
{
if(event.target.dataProvider != null )
{
(event.target as List).selectedIndex = 0;
}
}
You may not need to convert event.target to List. but it may help you access code completion while you are coding.
Actually, in thinking about this, you probably need to subclass the list and override the dataProvider setter.
override public function set dataProvider(data:*) : void {
super._dataProvider = data;
// This will be an ArrayCollection or XMLListCollection, so will have a length
if (data && data.length > 0) {
this.selectedIndex = 0;
invalidateDisplayList();
}
}
Set the dataProvider of the list, set the selected item, and then either call your handler function directly with a null parameter, or make the list dispatch an indexChanged event so that your handler function gets executed.
OK I have a ComboBox, the dataProvider is an array of objects with label properties that give the ComboBox the list of options.
Is there a way I can have a variable like mySelectedItem, and bind the ComboBox's selectedItem to it so that if it changes, the ComboBox's selectedItem will change to whatever it is?
I hope this makes sense.
Thanks!
Yes, ComboBox's selectedItem property is bindable.
It would go something like this:
<mx:ComboBox selectedItem="{mySelectedItem}">
</mx:ComboBox>
In your AS:
[Bindable]
var mySelectedItem:Object;
Changes to mySelectedItem should show up in ComboBox. You may get errors if the item referenced by mySelectedItem does not exist in the ComboBox's dataProvider.
On the surface, it's as simple as:
<mx:ComboBox id="myComboBox"
dataProvider="{myDataProvider}"
selectedItem="{defaultItem}"/>
When you set defaultItem (make sure it is [Bindable]) to one of the items in the data provider, it will update the control.
But there are problems with this approach. Unless currentDefaultItem always changes AFTER myDataProvider, the binding to dataProvider may undo the selection, reverting to the default (first item in the list).
One way around this is to force selectedItem to be rebound after dataProvider, by including dataProvider in the call providing the selectedItem.
<mx:ComboBox id="myComboBox"
dataProvider="{myDataProvider}"
selectedItem="{getSelectedItem(myComboBox.dataProvider, defaultItem)}"/>
What this does is ensure selectedItem will be rebound when either currentDefaultItem changes, or after the dataProvider changes. I'd be interested in other solutions myself.
Use an event listener for the Change event and do your processing there.
// update a label item's text with that of the Combobox's selectedItem
private function changeEvt(event:Event):void {
label.text =event.currentTarget.selectedItem.label + " " +
}
or, you could do something like this if you don't mind extending ComboBox;
This is pseudocode (sorry, identification of matches depends on the object type) - but you get the idea...
public class IndexRetainingComboBox extends ComboBox
{
public function IndexRetainingComboBox()
{
super();
}
override public function set dataProvider(value:Object):void
{
var originalSelection:Object = this.selectedItem;
super.dataProvider = value;
var newIdx:uint = [find originalSelection idx in combobox or return 0 ]
this.selectedIndex = newIdx;
}
}
I know this is how its described in the documentation.
As in a change to the selectedItem will fire the change listener. However for me, this does not happen. Anyone else encounter the same behavior?
This looks like a great approach: make the value attribute writeable:
http://flex.sys-con.com/node/312098
I have a Flex ComboBox that gets populated by a dataprovider all is well...
I would now like to add a default " -- select a item --" option at the 0 index, how can I do this and still use a dataprovider? I have not seen any examples of such, but I can't imagine this being hard...
If you don't need the default item to be selectable you can use the prompt property of ComboBox and set the selectedIndex to -1. That will show the string you set propmt to as the selected value until the user chooses another. It will not appear in the list of options, however.
I came across this problem today and wanted to share my solution.
I have a ComboBox that has an ArrayCollection containing Objects as it's dataprovider. When the application runs, it uses a RemoteObject to go out and get the ArrayCollection/Objects. In my event handler for that call I just have it append another object to the beginning of the ArrayCollection and select it:
var defaultOption:Object = {MyLabelField: "Select One"};
myDataProvider.addItemAt(defaultOption, 0);
myComboBox.selectedIndex = 0;
This is what my ComboBox looks like for reference:
<mx:ComboBox id="myComboBox" dataProvider="{myDataProvider}" labelField="MyLabelField" />
The way I've dealt with this in the past is to create a new collection to serve as the data provider for the combobox, and then I listen for changes to the original source (using an mx.BindingUtils.ChangeWatcher). When I get such a notification, I recreate my custom data provider.
I wish I knew a better way to approach this; I'll monitor this question just in case.
This can be used following code for selected default value of combobox
var index:String = "foo";
for(var objIndex:int = 0; objIndex < comboBox.dataProvider.length; objIndex++) {
if(comboBox.dataProvider[objIndex].label == index)
{
comboBox.selectedIndex = objIndex;
break;
}
}
<mx:ComboBox id="comboBox" dataProvider="{_pageIndexArray}" />