Grid id is set when you call
$g->render('list1');
Here list1 is set as grid id.

For subgrid, id is auto set, which can be read by
$g->id

Hi Abu,

The render thing doesn't work. I just an error.

– Jelmer

This is the error:

Fatal error: Call to undefined method C_DataGrid::render()

Our product does not support C_DataGrid object.
Please refer docs for more help at http://phpgrid.org/docs