How to add ComboBox to dynamically created DataGridColumn

[bon_t]

I can create my datagrid in mxml code with no issues. There are six columns, but I'm showing the code only for the column in question (the one with the ComboBox):

<mx:DataGrid x="82" y="189" width="100%" height="100%" editable="true" id="samplesDataGrid" dataProvider="{samplesData}">
<mx:columns>
<mx:DataGridColumn headerText="Tag" dataField="sem_tag" width="200" rendererIsEditor="true">
<mx:itemRenderer>
<fx:Component>
<mx:ComboBox width="190" prompt="{data.sem_tag}" dataProvider="{outerDocument.tagsAsStringsList}"/>
</fx:Component>
</mx:itemRenderer>
</mx:DataGridColumn>
</mx:columns>
</mx:DataGrid>


The dataProvider for the datagrid, samplesData, is an ArrayCollection populated by a method in the java backend that loads data from a file of samples. Each sample has a tag value.
The dataProvider for the ComboBox, tagsAsStringsList, is an ArrayCollection populated by a method in the java backend that loads data from a file of tags.
The ComboBox's prompt value is set to the tag value from the samplesData.

Now I need to create the DataGridColumns dynamically.
I have the following code (without adding the ComboBox to the column) which works:

public var columns:Array = ["index", "sem_tag", "count", "fake", "raw_transcription", "path"];

private function addDataGridColumn(dataField:String):void
{
var dgc:DataGridColumn = new DataGridColumn(dataField);
var cols:Array = samplesDataGrid.columns;
cols.push(dgc);
if ( dataField == "sem_tag" )
{
dgc.headerText = "Tag"; dgc.width = 200;
}
samplesDataGrid.columns = cols;
}


I've tried two ways to add the ComboBox with no luck.

ATTEMPT #1
I created a tagComboBox.as file:

package components
{
import mx.controls.ComboBox;

public class tagComboBox extends ComboBox
{
public function tagComboBox()
{
super();
width=190;
prompt=data.sem_tag;dataProvider=outerDocument.tag sAsStringsList;
}
}
}


The setting of the dataProvider gives me an error:
Access to undefined property outerDocument

I removed the dataProvider setting and added the following settings (in bold) in the addDataGridColumn method:

if ( dataField == "sem_tag" )
{
dgc.headerText = "Tag"; dgc.width = 200; dgc.rendererIsEditor = true; dgc.itemRenderer = components.tagComboBox;
}


When I run my application, I get the error:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
caused by my prompt=data.sem_tag setting in the tagComboBox.as file.

ATTEMPT #2
I created the comboBox in the addDataGridColum method:

if ( dataField == "sem_tag" )
{
var tagComboBox:mx.controls.ComboBox = new mx.controls.ComboBox();
tagComboBox.dataProvider = tagsAsStringsList;
dgc.headerText = "Tag"; dgc.width = 200; dgc.rendererIsEditor = true; dgc.itemRenderer = tagComboBox;
}


The setting of the itemRenderer gives me the following error:
Implicit coercion of a value of type mx.controls:ComboBox to an unrelated type mx.core:IFactory

I can’t even set
tagComboBox.prompt = samplesData.sem_tag
I get this error:
Access of possibly undefined property sem_tag through a reference with static type mx.collections:ArrayCollection.

Thanks in advance for your help!

[bon_t]

I solved my issue last Friday as follows:


var cf_tagComboBox:ClassFactory = new ClassFactory(mx.controls.ComboBox);

if ( dataField == "sem_tag" )
{
dgc.headerText = "Tag"; dgc.width = 200; dgc.rendererIsEditor = true; dgc.itemRenderer = cf_tagComboBox;
}

// When the dataProvider for the combo box gets populated.
protected function loadTagsAsStringsArray( event:ResultEvent ):void
{
tagsAsStringsList = loadTagsAsStringsResult.lastResult as ArrayCollection;
cf_tagComboBox.properties = { width:190, dataProvider:tagsAsStringsList };
}