Загрузка файла hasfile всегда ложь на стороне сервера

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Always" runat="server">
<ContentTemplate>

<div class="controls">
	<asp:FileUpload id="file" CssClass="btn btn-success span3" runat="server" />
</div>
<div class="controls">
	<asp:FileUpload id="file1" CssClass="btn btn-success span3" runat="server" />
</div> 

<asp:Button id="btnSubmit" runat="server" CssClass="btn btnprimary" Text="Submit" OnClientClick="return validate();" OnClick="btnSubmit_click"/>
<asp:Button id="btnUpdate" runat="server" CssClass="btn btn-success" Text="Update" OnClientClick="return validate();" OnClick="btnUpdate_click"/>



<triggers>
    <asp:PostBackTrigger ControlID = "btnSubmit" />
    <asp:PostBackTrigger ControlID = "btnUpdate" />