R – How to disable selected columns in a datagrid in flex for selected rows

You can manipulate the columns attached to the data grid using the .columns property. Bear in mind that this method is a getter and returns you a copy of the list of columns on the datagrid, so if you manipulate its contents you have to apply those changes back to the data grid using the equivalent setter, e.g.

<mx:DataGrid id="dg" />

in ActionScript code

var columns:Array = dg.column;
columns.push(new DataGridColumn("hello"));
dg.columns = columns;

In your case you could hold your master list of columns in a separate array and push them onto the data grid as the user checks and un-checks them from the list in your comboBox.

Alternatively you can iterate through the column list looking for the ones which are checked in your comboBox and set their .visible property accordingly.

HTH

The most basic solution is using the custom renderer and selection preventing logic you've mentioned:

DataGridRowDisabling.mxml

<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" xmlns:local="*">

    <fx:Script>
    <![CDATA[
        import spark.events.GridSelectionEvent;

        private function dataGrid_selectionChangingHandler(event:GridSelectionEvent):void
        {
            var index:int = event.selectionChange.rowIndex;
            var product:Product = dataGrid.dataProvider.getItemAt(index) as Product;
            if (product && !product.enabled)
                event.preventDefault();
        }

    ]]>
    </fx:Script>

    <s:DataGrid id="dataGrid" itemRenderer="GridItemRenderer2" selectionChanging="dataGrid_selectionChangingHandler(event)">
        <s:dataProvider>
            <s:ArrayCollection>
                <local:Product name="iPod" price="199.99"/>
                <local:Product name="iPad 3" price="499.99"/>
                <local:Product name="iPad 4" price="599.99" enabled="false"/>
                <local:Product name="iPad 5" price="699.99" enabled="false"/>
            </s:ArrayCollection>
        </s:dataProvider>
    </s:DataGrid>

</s:Application>

GridItemRenderer2.mxml

<s:GridItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009" 
    xmlns:s="library://ns.adobe.com/flex/spark" 
    xmlns:mx="library://ns.adobe.com/flex/mx" clipAndEnableScrolling="true">

    <fx:Script>
    <![CDATA[

        override public function prepare(hasBeenRecycled:Boolean):void 
        {
            if (data is Product)
                enabled = Product(data).enabled;

            lblData.text = data[column.dataField];
        }

    ]]>
    </fx:Script>

    <s:Label id="lblData" top="9" left="7"/>

</s:GridItemRenderer>

Product.as

package
{
public class Product
{

    public var name:String;

    public var price:Number;

    public var enabled:Boolean = true;

}
}