How to use FindControl method to find Html CheckBox inside GridView using C# in ASP.Net

hi I used below gridview and Imgsave (imagebutton) in page

<asp:GridView ID="GrdMessage" runat="server" AutoGenerateColumns="false" Font-Size="14px"
    OnRowDataBound="OnRowDataBound" PageSize="5" GridLines="Both" Width="338px" BorderColor="#808080"
    BorderStyle="Solid" BorderWidth="1px" RowStyle-BorderColor="#808080" RowStyle-BorderStyle="Solid"
    RowStyle-BorderWidth="1px" AlternatingRowStyle-BackColor="#C0C0C0" PagerStyle-HorizontalAlign="Center"
    PagerStyle-VerticalAlign="Middle" ShowHeader="False" Font-Names="behtop_Yekan"
    BackColor="#Fcfcfc" CssClass="gridGalary">
    <Columns>
        <asp:TemplateField ItemStyle-Width="0px">
            <ItemTemplate>
                <asp:Label ID="lblID" runat="server" Text='<%# Eval("ID")%>' Visible="false"></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField ItemStyle-Width="54px" ItemStyle-VerticalAlign="Middle" ItemStyle-Height="38px">
            <ItemTemplate>
                <label id="Label1" runat="server" class="chlinkDoc1">
                    <input type="checkbox" id="ChBpriceL" runat="server" class="chlinkDoc1" /></label>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField ItemStyle-Width="282px" ItemStyle-VerticalAlign="Middle">
            <ItemTemplate>
                <asp:Label ID="Lblname" runat="server" Text='<%#toPersianNumber(Eval("GroupName").ToString())%>'
                    CssClass="lblQGK"></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
    <asp:ImageButton ID="Imgsave" runat="server" CssClass="imgsaveMK" ImageUrl="~/Image/admin/savef.png"
        OnClick="ImgIjad_Click">
    </asp:ImageButton>

here in gridview I used checkbox:

<asp:TemplateField ItemStyle-Width="54px" ItemStyle-VerticalAlign="Middle" ItemStyle-Height="38px">
    <itemtemplate>
        <label id="Label2" runat="server" class="chlinkDoc1">
        <input type="checkbox" id="ChBpriceL" runat="server" class="chlinkDoc1"/></label>                                        
    </itemtemplate>
</asp:TemplateField>

I want when users xhecked one checkbox from gridview and click imgsave button: it saves that row's of gridview (Lblname.text) into database.

how I can do it?

best regards

neda