ASP.NET使用Ajax技术ModalPopupExtender控件问题？

在gridview中打开删除功能：
<asp:CommandField ShowDeleteButton="True" />
用ModalPopupExtender弹出panel：
<asp:Panel ID="panEditDelete" runat="server" Style="display: none" CssClass="modalPopup">
                <asp:Panel ID="panEditDelete_1" runat="server" Style="cursor: move; background-color: #DDDDDD;
                    border: solid 1px Gray; color: Black">
                    <div>
                        <p>
                            <br />
                            该表中存在数据，删除无法完成。<br />
                            <br />
                        </p>
                    </div>
                </asp:Panel>
                <div>
                    <p style="text-align: center;">
                        <input type="button" id="btnEditDelete" runat="server" value="确认" />
                    </p>
                </div>
            </asp:Panel>
        <asp:HiddenField ID="hfEditDelete" runat="server" />
        <cc1:ModalPopupExtender ID="mpeEditDelete" runat="server" TargetControlID="hfEditDelete"
                PopupControlID="panEditDelete" OkControlID="btnEditDelete" BackgroundCssClass="modalBackground">
            </cc1:ModalPopupExtender>想实现的效果是当点击删除后，弹出该Panel，并结束删除<asp:Panel ID="panOKDelete" runat="server" Style="display: none" CssClass="modalPopup">
                <asp:Panel ID="panOKDelete_1" runat="server" Style="cursor: move; background-color: #DDDDDD;
                    border: solid 1px Gray; color: Black">
                    <div>
                        <p>
                            <br />
                            是否删除？删除后数据将不可恢复。<br />
                            <br />
                        </p>
                    </div>
                </asp:Panel>
                <div>
                    <p style="text-align: center;">
                        <asp:Button ID="btnOKDelete" runat="server" Text="确认" OnClick="btnOKDelete_Click" />
                        <asp:Button ID="btnCancelDelete" runat="server" Text="取消" />
                    </p>
                </div>
            </asp:Panel>
        <asp:HiddenField ID="hfOKDelete" runat="server" />
        <cc1:ModalPopupExtender ID="mpeOKDelete" runat="server" TargetControlID="hfOKDelete"
                PopupControlID="panOKDelete" CancelControlID="btnCancelDelete" BackgroundCssClass="modalBackground">
            </cc1:ModalPopupExtender>
想实现的效果是当点击删除后，弹出该Panel，点击确认，删除，点击取消，结束删除功能问题是当点击删除后，不管是否弹出Panel，都将数据删除，我知道缺少某个事件，要用到HiddenField，但不知怎么实现.....求解