how to add columns programmatically and set grouping on advancedDataGrid control in flex ?

Question

on advancedDataGridControl in flex3 , how to do the following:

1. Add Columns at runtime ( programmatically )
2. Specify the column grouping ( programmatically )
3. set method to be used to show summary row ( programmatically)

Answer 1

This is how you can add columns at runtime.

private var columns:ArrayCollection;// Array collection of data

public function createColumns():Array{
    var advancedDataGridColumn:AdvancedDataGridColumn;
    var i:int;
    var columnsArray:Array = new Array();
    for(i=0;i<columns.length;i++){  
        advancedDataGridColumn=new AdvancedDataGridColumn();
        advancedDataGridColumn.headerText=columns[i].dispheader.toString();
        advancedDataGridColumn.dataField="@"+columns[i].name.toString();
        advancedDataGridColumn.itemRenderer=new ClassFactory(Styler);         if(columns[i].descending!=undefined ){
         if(columns[i].descending.toString()=="true")
          sortField = new SortField("@"+columns[i].name.toString(),false,true,null);
         else
          sortField = new SortField("@"+columns[i].name.toString(),false,false,null);
        }
        return columnsArray;
    }

and set columns like

ADDataGrid.columns=createColumns();

similarly you can set vaulue in

ADDataGrid.groupedColumns

and last one i didn't get it can you please explain a little more