无法在asp：UpdatePanel内的asp：formview中上传文件？

This is the aspx file:-

这是aspx文件: -

<ajaxToolkit:ModalPopupExtender ID="ModalProgress" runat="server" TargetControlID="panelUpdateProgress" BackgroundCssClass="modalBackground" PopupControlID="panelUpdateProgress" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:FormView ID="formviewReg" runat="server" Width="100%" AllowPaging="false" OnItemUpdating="formviewReg_ItemUpdating">
<EditItemTemplate>
<asp:LinkButton ID="lbtnupdatepersonal" runat="server" OnClick="lbtnupdatepersonal_Click" ValidationGroup="g1">Update</asp:LinkButton>
<asp:FileUpload ID="FileUpload1" runat="server" />
</EditItemTemplate>
<ItemTemplate>
<asp:LinkButton ID="lbtneditpersonal" runat="server" OnClick="lbtneditpersonal_Click">Edit</asp:LinkButton>
//some html controls
</ItemTemplate>
</asp:FormView>
</ContentTemplate>
</asp:UpdatePanel>
<ajaxT