Error #1009 at mx.controls::DataGrid/mx.controls:DataGrid::mouseUpHandler()

Question

Hello.
At first sorry for my english.
I have encountered problem with DataGrid control.
There is DataGrid control, which have custom ItemRenderer
(MulticolorDataGridItemRenderer).
This DataGrid control has several properties:
1) click on a row changes it background color
2) click on "Filter ON" button, filter DataGrid by "status"
field
"TypeError: Error #1009: Cannot access a property or method
of a null object reference.
at
mx.controls::DataGrid/mx.controls:DataGrid::mouseUpHandler()"
This error occure when filter is ON, by click on a row. It
occures occasionally. I note that it
occur when DataGrid's vertical scrollbar is not in top
position.
If I remove recovering of scroll position, this bug
disappear.
Sample code:
~~~~~~~~~~~~
1. Application mxml:
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="
http://www.adobe.com/2006/mxml"
layout="absolute">
<mx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.controls.List;
private var objPrevSelectedItem:Object = null;
private var arrList:Array = [{name: "Matt", lastname:
"Chotin", status: "0", selected: "0"},
{name: "Ely", lastname: "Greenfield", status: "1", selected:
"0"},
{name: "Christophe", lastname: "Coenraets", status: "2",
selected: "0"},
{name: "Sho", lastname: "Kuwamoto", status: "1", selected:
"0"},
{name: "Steven", lastname: "Webster", status: "4", selected:
"0"},
{name: "Alistair", lastname: "McLeod", status: "3",
selected: "0"},
{name: "Chafic", lastname: "Kazoun", status: "1", selected:
"0"},
{name: "Manish", lastname: "Jethani", status: "2", selected:
"0"},
{name: "Mike", lastname: "Chambers", status: "4", selected:
"0"},
{name: "Ted", lastname: "Patrick", status: "0", selected:
"0"},
{name: "Roger", lastname: "Gonzales", status: "1", selected:
"0"},
{name: "David", lastname: "Zuckerman", status: "3",
selected: "0"},
{name: "Alex", lastname: "Uhlmann", status: "3", selected:
"0"},
{name: "Peter", lastname: "Ent", status: "3", selected:
"0"},
{name: "Adobe", lastname: "Consulting", status: "2",
selected: "0"},
{name: "Marcel", lastname: "Boucher", status: "4", selected:
"0"},
{name: "Andrew", lastname: "Trice", status: "1", selected:
"0"},
{name: "Mike", lastname: "Morearty", status: "1", selected:
"0"},
{name: "Everything", lastname: "Flex", status: "0",
selected: "0"},
{name: "Jesse", lastname: "Warden", status: "3", selected:
"0"},
{name: "Richinternet", lastname: "Blog", status: "2",
selected: "0"},
{name: "Flex", lastname: "Daddy", status: "2", selected:
"0"},
{name: "Keun", lastname: "Lee", status: "0", selected: "0"},
{name: "David", lastname: "Koletta", status: "4", selected:
"0"},
{name: "Brian", lastname: "Deitte", status: "1", selected:
"0"},
{name: "Darron", lastname: "Schal", status: "2", selected:
"0"},
{name: "Narciso", lastname: "Jaramillo", status: "3",
selected: "0"},
{name: "Kiwi", lastname: "Teamblog", status: "4", selected:
"0"},
{name: "Anthony", lastname: "Rumsey", status: "0", selected:
"0"}];
[Bindable]
private var arrcollDP:ArrayCollection = new
ArrayCollection(arrList);
private function fnSelectRow(event:Event):void
if (objPrevSelectedItem != null)
objPrevSelectedItem["selected"] = new String("0");
ArrayCollection(DataGrid(event.target).dataProvider).itemUpdated(objPrevSelectedItem);
var numScrolPos:Number =
DataGrid(event.target).verticalScrollPosition;
Object(DataGrid(event.target).selectedItem)["selected"] =
new String("1");
ArrayCollection(DataGrid(event.target).dataProvider).itemUpdated(DataGrid(event.target).s electedItem);
objPrevSelectedItem =
Object(DataGrid(event.target).selectedItem);
if (arrcollDP.filterFunction != null)
arrcollDP.filterFunction = fnFilter;
arrcollDP.refresh();
DataGrid(event.target).verticalScrollPosition = numScrolPos;
private function fnFilter(item:Object):Boolean
var bResult:Boolean = new Boolean(false);
if (String(item["status"]) == "0")
bResult = true;
return bResult;
]]>
</mx:Script>
<mx:DataGrid
width="100%"
height="100"
dataProvider="{arrcollDP}"
itemRenderer="MulticolorDataGridItemRenderer"
draggableColumns="false"
rowHeight="17"
paddingTop="1"
paddingBottom="1"
horizontalGridLineColor="#a0a0a0"
horizontalGridLines="true"
change="fnSelectRow(event)">
<mx:columns>
<mx:DataGridColumn headerText="Name" dataField="name"
width="250" textAlign="left" sortable="false"/>
<mx:DataGridColumn headerText="Last Name"
dataField="lastname" width="250" textAlign="left"
sortable="false"/>
<mx:DataGridColumn headerText="Status" dataField="status"
width="80" textAlign="center" sortable="false"/>
</mx:columns>
</mx:DataGrid>
<mx:Button label="Filter ON" y="110" x="5"
click="arrcollDP.filterFunction = fnFilter;
arrcollDP.refresh();"/>
<mx:Button label="Filter OFF" y="110" x="105"
click="arrcollDP.filterFunction = null; arrcollDP.refresh();"/>
</mx:Application>
2. MulticolorDataGridItemRenderer component mxml:
<?xml version="1.0" encoding="utf-8"?>
<mx:DataGridItemRenderer xmlns:mx="
http://www.adobe.com/2006/mxml"
background="true" dataChange="fnChangeColor(event);">
<mx:Script>
<![CDATA[
import mx.controls.dataGridClasses.DataGridColumn;
import mx.events.FlexEvent;
import mx.controls.Alert;
private function fnChangeColor(event:FlexEvent):void
if (Object(this.data) != null)
if (!(this.data is DataGridColumn))
var strTmp:String = String(Object(this.data)["status"]);
if (strTmp == "0")
this.backgroundColor = 0xccffcc;
else if (strTmp == "1")
this.backgroundColor = 0xffff99;
else if (strTmp == "2")
this.backgroundColor = 0x99ccff;
else if (strTmp == "3")
this.backgroundColor = 0xffcc99;
else if (strTmp == "4")
this.backgroundColor = 0xcc66ff;
if (String(Object(this.data)["selected"]) == "1")
this.backgroundColor = 0xff9933;
]]>
</mx:Script>
</mx:DataGridItemRenderer>
And one another question: why did disappear standard DataGrid
control selection mechanism, when I used custom
DataGridItemRenderer? Try to use the sample code above withou
fnSelectRow function.
TIA

Answer 1

Hi, I will try to explain what i have undestood about this issue.
I have an application that loads at runtime some modules, and in my project configuration (Flex Modules), i specified some modules to compile optimizing to main application. Besides that, my project uses RSL to the framework linkage, and i perceived that the compiler output reports some warning messages just like "The CSS type selector 'DataGrid' was not processed, because the type was not used in the application." or others similars "The CSS type selector 'TextArea' was not processed, because the type was not used in the application.".
When i run the application, and click the first time in some grid column, the error "Type Coercion failed: cannot convert ......@abcda2 to ........." happens.
It happens because, these controls or components has not been linked in the main application compilation, and so, when you use the first module that uses one of these components, only the module loads an instance of these components and maintain on its part of memory.
Dispite of being loaded in the main application, each module and main application has its SystemManager instance to register and load components, and because of it, when the application try to cast instances of the same component, but at differents SystemManager's singleton implementations, the above error occurs.
So my solution was to add some reference of the controls or components that appears at the warning messages that was not compiled, to force the main application compilation to add these components at its SystemManager singletons first than any module.
Only add the name of the component and import its package. Do not have to add to the stage. See below.
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" ....>
<mx:Script>
        <![CDATA[
                    DataGrid;
                    TextArea;
        ]]>
    </mx:Script>
</mx:Application>