protected void btn_chamnhuanbut_click(object sender, EventArgs e)
        {
            foreach (DataGridItem m_Item in DataGrid_tinbai.Items)
            {
                CheckBox chk_Select  = (CheckBox)m_Item.FindControl("optSelect");
                Label    lblMaTacGia = (Label)m_Item.FindControl("lblMaTacGia");

                if (chk_Select != null && chk_Select.Checked)
                {
                    double    id          = double.Parse(DataGrid_tinbai.DataKeys[int.Parse(m_Item.ItemIndex.ToString())].ToString());
                    string    sql         = "select THANHTOAN from T_NhuanBut where Ma_TinBai=" + id + " and  Ma_tacgia=" + lblMaTacGia.Text;
                    UltilFunc ulti        = new UltilFunc();
                    DataTable dtthanhtoan = ulti.ExecSqlDataSet(sql).Tables[0];
                    bool      check       = false;
                    if (dtthanhtoan.Rows[0]["THANHTOAN"].ToString() != DBNull.Value.ToString())
                    {
                        check = (bool)dtthanhtoan.Rows[0]["THANHTOAN"];
                    }
                    if (check)
                    {
                        Daltinbai.Sp_UpdateThanhToanNhuanButTinBai(id, double.Parse(lblMaTacGia.Text), false, DateTime.Now, _user.UserID);
                    }
                    else
                    {
                        Daltinbai.Sp_UpdateThanhToanNhuanButTinBai(id, double.Parse(lblMaTacGia.Text), true, DateTime.Now, _user.UserID);
                    }
                }
            }
            LoadData();
        }