Maintain ViewState of Checkbox checked on paging in asp.net

I have a Gridview with some data. In that I have 5 rows of paging. Whenever I check on checkbox in first page and go to second page and again I come to first page. The checkbox check value gets disappear.

The value of checked is not retained. How to get it maintain the viewstate of checkbox. Please suggest

CODE:

<asp:GridView ID="grdDisplayCMMData" runat="server" AutoGenerateColumns="false" Width="100%" ShowHeaderWhenEmpty="true" CssClass="heavyTable table" EmptyDataText="No records to display"
            AllowPaging="true" PageSize="2" OnPageIndexChanging="grdDisplayCMMData_PageIndexChanging">
            <Columns>                    
                <asp:TemplateField HeaderText="ID" Visible="false">
                    <ItemTemplate>
                        <asp:Label ID="lblID_CMM" runat="server" Text='<%#Eval("ID") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="SAP ID">
                    <ItemTemplate>
                        <asp:Label ID="lblSAP_ID_CMM" runat="server" Text='<%#Eval("SAP_ID") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="ID OD CHANGE">
                    <ItemTemplate>
                        <asp:Label ID="lblID_OD_COUNTCHANGE_CMM" runat="server" Text='<%#Eval("ID_OD_COUNTCHANGE") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="ID OD CHANGE DATE">
                    <ItemTemplate>
                        <asp:Label ID="lblID_OD_CHANGEDDATE_CMM" runat="server" Text='<%#Eval("ID_OD_CHANGEDDATE") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="RRH COUNT CHANGE">
                    <ItemTemplate>
                        <asp:Label ID="lblRRH_COUNTCHANGE_CMM" runat="server" Text='<%#Eval("RRH_COUNTCHANGE") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="RRH COUNT CHANGE DATE">
                    <ItemTemplate>
                        <asp:Label ID="lblRRH_CHANGEDDATE_CMM" runat="server" Text='<%#Eval("RRH_CHANGEDDATE") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="TENANCY COUNT CHANGE">
                    <ItemTemplate>
                        <asp:Label ID="lblTENANCY_COUNTCHANGE_CMM" runat="server" Text='<%#Eval("TENANCY_COUNTCHANGE") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="TENANCY COUNT CHANGE DATE">
                    <ItemTemplate>
                        <asp:Label ID="lblTENANCY_CHANGEDDATE_CMM" runat="server" Text='<%#Eval("TENANCY_CHANGEDDATE") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="STATUS">
                    <ItemTemplate>
                        <asp:Label ID="lblSTATUS_CMM" runat="server" Text='<%#Eval("STATUS") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="CREATED BY" Visible="false">
                    <ItemTemplate>
                        <asp:Label ID="lblCREATEDBY_CMM" runat="server" Text='<%#Eval("CREATED_BY") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Approve/Reject">
                    <ItemTemplate>
                        <asp:CheckBox ID="chkApprRejCMM" runat="server" />
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>                
        </asp:GridView>

SERVER CODE

protected void grdDisplayCMMData_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        try
        {
            BindCMMData();
            grdDisplayCMMData.PageIndex = e.NewPageIndex;
            grdDisplayCMMData.DataBind();               
        }
        catch (Exception ex)
        {
            string strErrorMsg = ex.Message.ToString() + " " + "StackTrace :" + ex.StackTrace.ToString();
            CommonDB.WriteLog("ERROR:" + strErrorMsg, ConfigurationManager.AppSettings["IPCOLO_LOG"].ToString());
        }
    }

Let me know if anything else is required