help my DataSet and DataGrid

[NhocTi]

why DataGird doesn't show String field.
my DataGrid : userGrid
my DataSet : userData

and in component insepecter I'm already set dataProvider for userGrid. in action code frame i use that code

var recData = new Array();
for( var i:Number=0; i<100; i++ ) {
recData[i]= {id:i, fullname:String("name"+i), price:i*.5};
}
userData.items = recData;


but when I test this movie, grid only show Number field, the fullname field doesn't have data in it.
help me, why? and how to fix?
thanks