Recently when I was working on Flex application and found that there is an issue with the columns of DataGrid, which is defined inside the repeater. Flex throws following error when you try to assign id or data binding values to DataGridColumn
“Unable to generate initialization code within Repeater, due to id or data binding on a component that is not a visual child.”
Which means if you want to assign dynamic value to say HeaderText of the column then you cannot use dynamically or id to assign value. Work around to this issue is to use columns array of datagrid to define the value. Click here to see the example and source code to use the column of the DataGrid.