Grid RowDatabound and PageIndexing

protected void gvwtest_RowDataBound(object sender, GridViewRowEventArgs e)
 {
     if (e.Row.RowType == DataControlRowType.DataRow)
     {
     ImageButton ibtnDelete = e.Row.FindControl("ibtnDelete") as ImageButton;
     ibtnDelete.Attributes.Add("onclick", "return(confirm('Are you sure you want to delete the Name?'))");
     }

 }




 protected void gvwtest_PageIndexChanging(object sender, GridViewPageEventArgs e)
  {
      gvwtest.PageIndex = e.NewPageIndex;
      FillGrid();
 }