Getting flex datagrid cell value using column and row indices - apache-flex

Question

i'm using flex for an application but i'm having some trouble to recover data from a datagrid that has a checkbox in one of the columns, the problem is that i can't use the function selectedIndex or selectedItem, because they are used to save the checked items.
Is there a way to recovery the datagrid informations using the column and row indices? Something like:
MyDataGrid[row][column] or MyDataProvider[row][column] or any combination of functions to allow me recovery an information using only the row and column.
Thanks

Answer 1

If you just want to be able to get a cell value of the data grid using row and col indices, you can extend the DataGrid component and add one simple function.
Here is a working example.
It looks something like this:
//CustomDataGrid
<?xml version="1.0" encoding="utf-8"?>
<s:DataGrid xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
width="400" height="300">
<fx:Script>
<![CDATA[
import spark.components.gridClasses.GridColumn;
public function getElementAt(row:int, col:int):Object
{
if (this.dataProvider.length < row + 1 || this.columns.length < col + 1)
return null;
else
return this.dataProvider.getItemAt(row)[(this.columns.getItemAt(col) as GridColumn).dataField];
}
]]>
</fx:Script>
</s:DataGrid>
Then you call it in your application like this:
//App
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
minWidth="955" minHeight="600"
xmlns:dgrc="com.dgrc.*">
<fx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.controls.Alert;
[Bindable]private var collection:ArrayCollection = new ArrayCollection([
{fld01:1, fld02:"fld02", fld03:"fld13", fld04:"fld14"},
{fld01:2, fld02:"fld02", fld03:"fld23", fld04:"fld24"},
{fld01:3, fld02:"fld02", fld03:"fld33", fld04:"fld34"},
{fld01:4, fld02:"fld02", fld03:"fld43", fld04:"fld44"},
{fld01:5, fld02:"fld02", fld03:"fld53", fld04:"fld54"}
]);
protected function getElement():void
{
var obj:Object = myDG.getElementAt(nsRow.value, nsCol.value);
Alert.show(String(obj));
}
]]>
</fx:Script>
<s:VGroup x="20" y="20">
<s:HGroup>
<s:NumericStepper id="nsRow" minimum="0" value="0"/>
<s:NumericStepper id="nsCol" minimum="0" value="0"/>
<s:Button label="Get It!" click="getElement()"/>
</s:HGroup>
<dgrc:CustomDataGrid id="myDG" width="300" height="160" dataProvider="{collection}">
<dgrc:columns>
<s:ArrayList>
<s:GridColumn dataField="fld01" headerText="Field 1" width="100"/>
<s:GridColumn dataField="fld03" headerText="Field 3" width="100"/>
<s:GridColumn dataField="fld04" headerText="Field 4"/>
</s:ArrayList>
</dgrc:columns>
</dgrc:CustomDataGrid>
</s:VGroup>
</s:Application>
Be aware that the row and col indices in this example refer a cell of the data grid and not a value of the data grid provider.
If you call
getElementAt(0, 1)
you will get "fld13"

Answer 2

If you are using the original DataGrid control, it is better to use the itemToLabel method of DataGridColumn, because item[dataField] will cause an exception when the property value contains dot notation, such as "customer.name":
public function getElementAt(row:int, col:int):Object {
var item:Object = dataProvider.getItemAt(row)
var column:DataGridColumn = dataGrid.columns[column] as DataGridColumn;
var value:String = column.itemToLabel(item);
return value;
}
This same method is used by the framework to provide the text displayed in the grid cell. If your checkbox in the grid is driven by a boolean property, the returned value will be true or false.