protected void cb1_Init(object sender, EventArgs e)
        {
            ASPxCheckBox cb = sender as ASPxCheckBox;
            GridViewDataItemTemplateContainer container = cb.NamingContainer as GridViewDataItemTemplateContainer;
            cb.ID = "cb" + container.KeyValue;
        }

        protected void chkIndicator_CheckChanged(object sender, EventArgs e)
        {
            ASPxCheckBox cb = sender as ASPxCheckBox;
            string key = ((GridViewDataItemTemplateContainer)cb.NamingContainer).KeyValue.ToString();
            AdministrationDataContext dc = new AdministrationDataContext();

            List<IndicatorDashboardList> indicatorList = null;
            if (ViewState["dsDashbordIndicators"] == null)
            {
                indicatorList = dc.GetIndicatorsForSelectedDashboard(ViewState["DashboardKey"].ToString()).ToList();
            }
            else
            {
                indicatorList = (List<IndicatorDashboardList>)ViewState["dsDashbordIndicators"];
            }

            var row = indicatorList.Where(ds => ds.KeyField == key).FirstOrDefault();

            if (row != null)
            {
                row.Included = cb.Checked ? "Y" : "N";
            }
            ViewState["dsDashbordIndicators"] = indicatorList;
        }





<asp:UpdatePanel ID="indicatorsPanel" runat="server">
                    <ContentTemplate>
                        <dxwgv:ASPxGridView ID="indicatorsGridView" ClientInstanceName="indicatorsGrid" runat="server" AutoGenerateColumns="False" 
                            OnAfterPerformCallback="indicatorsGridView_CallBack" KeyFieldName="KeyField" Width="80%">
                            <SettingsPager AllButton-Visible="true"></SettingsPager>
                            <Settings ShowFilterRow="true" ShowFilterRowMenu="true" />
                            <Columns>
                                <dxwgv:GridViewDataTextColumn Caption="Indicator Name" FieldName="Name" CellStyle-HorizontalAlign="Left" />
                                <dxwgv:GridViewDataTextColumn Caption="Select" FieldName="Included">
                                    <Settings  AllowAutoFilter="False" />
                                    <DataItemTemplate>
                                        <dxe:ASPxCheckBox ID="chkIndicator"  runat="server" Value='<%# Eval("KeyField") %>' Checked='<%# Eval("Included").ToString() == "Y" %>' AutoPostBack="true" OnCheckedChanged="chkIndicator_CheckChanged" onInit="cb1_Init">
                                        </dxe:ASPxCheckBox>
                                    </DataItemTemplate>
                                    <CellStyle HorizontalAlign="Center"/>
                                </dxwgv:GridViewDataTextColumn>
                            </Columns>
                        </dxwgv:ASPxGridView>

                        <!-- Clear Filter Button -->
                        <table class="ClearFilterTable" onclick="indicatorsGrid.ClearFilter();">
                            <tr>
                                <td><asp:Image id="imgClearIndicatorsGrid" runat="server" AlternateText="ClearFilter" ImageUrl="~/Images/FilterRemove.gif"  CssClass="ClearFilterImage"/></td>
                                <td>Clear Filter&nbsp;</td>
                            </tr>
                        </table>
                    </ContentTemplate>
                </asp:UpdatePanel>