So If you wanted to find any control forexample textbox named txtQty from datarow of your gridview,
You can use Gridview's onRowDataBound method for that purpose.>
You can use like.....
protected void GridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
TextBox lb = (TextBox)(e.Row.Cells[0].Controls[0]);
}
}
Hope it will help.... :)