Find CheckBox inside GridView in RowUpdating event using C# in ASP.Net

Hello,

I'm trying to update a record in db from a datagrid. My problem is that the checkboxes are not getting updated. Here's my code:

  <asp:GridView ID="gvChecks" runat="server" AutoGenerateColumns="false"
            OnRowCancelingEdit="gvChecks_RowCancelingEdit" 
            OnRowEditing="gvChecks_RowEditing" 
            OnRowUpdating="gvChecks_RowUpdating"  CssClass="mGrid" OnRowDataBound="gvChecks_RowDataBound">
            <Columns>
            <asp:TemplateField HeaderText="UploadDocID" ItemStyle-Width="25" Visible="false" >
                <ItemTemplate>
                    <asp:Label ID="lblUploadDocID" runat="server" Text='<%#Eval("UploadDocID") %>' Width="25"></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>        
                 <asp:TemplateField HeaderText="Description">
                <ItemTemplate>
                    <asp:Label ID="lblFileDescr" runat="server" Text='<%#Eval("FileDescr") %>' Width="500"></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>
 
           <asp:TemplateField HeaderText="CheckResult" Visible="false">
                <ItemTemplate>
                    <asp:Label ID="lblCheckResult" runat="server" Text='<%#Eval("DocValid") %>' Width="50"></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>                             
           <asp:TemplateField HeaderText="Yes" >
                <ItemTemplate>
                 <asp:CheckBox ID="cbYes" runat="server" Enabled="false"/>        
                </ItemTemplate>
                <EditItemTemplate>                  
                    <asp:CheckBox ID="cbYes" runat="server"/>  
                </EditItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="No" ItemStyle-Width="60">
                <ItemTemplate>
                 <asp:CheckBox ID="cbNo" runat="server" Enabled="false" />         
                </ItemTemplate>
                <EditItemTemplate>                   
                     <asp:CheckBox ID="cbNo" runat="server"/>  
                </EditItemTemplate>
            </asp:TemplateField>        
                 <asp:TemplateField ItemStyle-Width="150" >
                    <ItemTemplate>
                        <asp:LinkButton ID="btnEdit" Text="Edit" runat="server" CommandName="Edit"/>                      
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:LinkButton ID="btnUpdate" Text="Update" runat="server" CommandName="Update"/>
                        <asp:LinkButton ID="btnCancel" Text="Cancel" runat="server" CommandName="Cancel"/>
                    </EditItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>

  protected void gvChecks_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            try
            {
                Label checkID = (Label)gvChecks.Rows[e.RowIndex].FindControl("lblUploadDocID");
                CheckBox resYes = (CheckBox)gvChecks.Rows[e.RowIndex].FindControl("cbYes");
                CheckBox resNo = (CheckBox)gvChecks.Rows[e.RowIndex].FindControl("cbNo");
                string status = String.Empty; 

                if (resYes.Checked && resNo.Checked)
                    appObj.myMessageBox("You can only choose one checkbox.");
                else
                {
                    if (resYes.Checked)
                        status = "TRUE";
                    else
                      if (resNo.Checked)
                       status = "FALSE"; 
                    else
                        status = String.Empty;

                }

                    updateApplicationCheckList(checkID.Text, status);
                    gvChecks.EditIndex = -1;
                    bindApplicationChecks();
           }
            catch (Exception ex)
            {
                myMessageBox(ex.Message);
            }
        }

status is always empty. 

I would appreciate any kind of help.

Thank you.