[flexcoders] Re: DataGrid | ItemRenderers | Validation

[valdhor]

I would be inclined to extend the datagrid and add a variable to handle
this. You can compute the total from the dataprovider when it arrives
from the server and pass that in as a bound variable to the custom
datagrid. Example follows...

Application:
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml";
layout="vertical"
     xmlns:local="*">
     <mx:Script>
         <![CDATA[
             [Bindable] private var total:int = 101;
             private var dp:Array = [
                 {symbol: "ADBE", name: "Adobe Systems Inc.",
dateIncorporated: "3/1/50"},
                 {symbol: "MACR", name: "Macromedia Inc.",
dateIncorporated: "1/1/84"},
                 {symbol: "MSFT", name: "Microsoft Corp.",
dateIncorporated: "11/24/71"},
                 {symbol: "IBM", name: "IBM Corp.", dateIncorporated:
"9/14/63"}
                 ];
         ]]>
     </mx:Script>
     <local:MyExtendedDataGrid id="dg" initialize="dg.dataProvider = dp"
verticalAlign="middle"
         total="{total}">
         <local:columns>
             <mx:DataGridColumn headerText="Name" dataField="name"
width="140"/>
             <mx:DataGridColumn headerText="Symbol" dataField="symbol"
width="60" />
             <mx:DataGridColumn headerText="Date"
dataField="dateIncorporated" width="100"
itemRenderer="ItemRenderers.TotalRenderer" />
         </local:columns>
     </local:MyExtendedDataGrid>
</mx:Application>

MyExtendedDataGrid.as
package
{
     import mx.controls.DataGrid;

     public class MyExtendedDataGrid extends DataGrid
     {
         private static var _total:int;

         public function MyExtendedDataGrid()
         {
             super();
         }

         public function set total(totalToSet:int):void {_total =
totalToSet}

         public function get total():int {return _total}
     }
}

TotalRenderer.as
<?xml version="1.0" encoding="utf-8"?>
<mx:Label xmlns:mx="http://www.adobe.com/2006/mxml";>
     <mx:Script>
         <![CDATA[
             import mx.controls.dataGridClasses.DataGridListData;

             override public function set data(value:Object):void
             {
                 if(value != null)
                 {
                     super.data = value;
                     text = value[DataGridListData(listData).dataField];
                     if(MyExtendedDataGrid(listData.owner).total == 100)
                     {
                         setStyle("color", "#FF0000");
                     }
                     else
                     {
                         setStyle("color", "#0000FF");
                     }
                 }
             }
         ]]>
     </mx:Script>
</mx:Label>



HTH




Steve


--- In flexcoders@yahoogroups.com, Neil Webb <nwebb.co...@...> wrote:
>
> Hi, just looking for advice on the most appropriate way to approach
this (or
> links to existing examples) :)
>
> I've got a DataGrid, and the items use a subclass of NumericStepper.
This
> stepper validates itself depending on the total of *all *items in that
> column  (i.e. it styles itself green if the column-total adds up to,
say,
> 100, or red if the column-total is <> 100). In other words, a single
> itemRenderer needs knowledge of the values of ALL renderers in that
column.
>
> I'm aware that itemRenderers should only take care of setting
themselves,
> due to recycling -  (ie Adobe don't intend developers to get hold of a
list
> of all renderers, cycle over them and set properties on them
externally).
>
> In this case however, in order to validate a *single *renderer I need
to
> know about the total of all renderers within a single column.
Currently I
> have things working - I give each renderer knowledge of its owner's
> dataProvider - then, in the renderer's validation method I loop
through all
> items in the dp, total them up and set the style accordingly.
>
> However, this feels wrong. Also, it's not so bad if I have a
> PercentageStepper, where I could hardcode the total as 100, but what
about
> columns where the user has a set amount of cash, and the total of all
> Steppers must equal that cash-value? In that case, using my setup,
> *each *renderer
> also needs to know the total cash amount, which means setting it on
each
> renderer (easy to do, but again it feels wrong).
>
> So in a nutshell I guess I'm saying, what's the preferred way of
validating
> an itemRenderer, when the validation of that renderer depends on
properties
> of all the itemRenderers in that column?
>
> Thanks
>