FileUpload控件问题

Question

我用FileUpload上传文件，可是HasFile属性总是False，不管我有没有选择文件。

后来我用ajax tool kit的AsyncFileUpload，然后选择完文件就提示File Attached Invalid。

我的代码：

<%@ Page Title="管理乐谱" Language="C#" MasterPageFile="~/Content/Default.Master" AutoEventWireup="true" CodeBehind="Manage.aspx.cs" Inherits="MusicGod.Scores.Manage" %>

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajax" %>
<asp:Content ID="Content1" ContentPlaceHolderID="Head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="Main" runat="server">
    <asp:ListView ID="ListView1" DataKeyNames="Id" runat="server" InsertItemPosition="LastItem" ItemType="MusicGod.Models.MusicPage" SelectMethod="ListView1_GetData" InsertMethod="ListView1_InsertItem" DeleteMethod="ListView1_DeleteItem">
        <InsertItemTemplate>
            <li>
                页码: 
                <asp:TextBox ID="Num" runat="server" Text='<%# BindItem.Num %>'/>
                <asp:RequiredFieldValidator ID="reqNum" ErrorMessage="请输入页码" ControlToValidate="Num" runat="server" Text="*" CssClass="ErrorMsg" /><br />

                图像文件: 
                <ajax:AsyncFileUpload ID="UrlUpload" runat="server" />
                <asp:CustomValidator ID="cusUrl" ErrorMessage="请选择 .png 文件" runat="server" Text="*" CssClass="ErrorMsg" /><br />

                <asp:Button ID="InsertBtn" Text="添加" runat="server" CommandName="Insert" /><br />
                <asp:ValidationSummary ID="ValidationSummary1" runat="server" />
            </li>
        </InsertItemTemplate>
        <ItemTemplate>
            <li>
                <asp:Image ImageUrl='<%# Item.Url %>' runat="server" /><br />
                第<asp:Literal ID="Num" runat="server" Text='<%# Item.Num %>'></asp:Literal>页<br />

                <asp:Button ID="DeleteBtn" Text="删除" runat="server" CommandName="Delete" />
            </li>
        </ItemTemplate>
        <LayoutTemplate>
            <h1>管理乐谱</h1>
            <ul class="ItemContainer">
                <li id="itemPlaceHolder" runat="server"></li>
            </ul>
        </LayoutTemplate>
    </asp:ListView>
</asp:Content>

public void ListView1_InsertItem([QueryString("ScoreId")]int scoreId)
        {
            var item = new MusicGod.Models.MusicPage();
            TryUpdateModel(item);
            AsyncFileUpload urlUpLoad = (AsyncFileUpload)ListView1.InsertItem.FindControl("UrlUpload");
            if (!urlUpLoad.HasFile || !urlUpLoad.FileName.ToLower().EndsWith(".png"))
            {
                CustomValidator cusUrl = (CustomValidator)ListView1.InsertItem.FindControl("cusUrl");
                cusUrl.IsValid = false;
                ModelState.AddModelError("Invalid", cusUrl.ErrorMessage);
            }
            if (ModelState.IsValid && Page.IsValid)
            {
                // Save changes here
                using (var entities = new MGEntities())
                {
                    item.ScoreId = scoreId;

                    string virFolder = "~/Resrc/";
                    string serverPath = Server.MapPath(virFolder);
                    string fileName = Guid.NewGuid().ToString();
                    string ext = ".png";

                    urlUpLoad.SaveAs(Path.Combine(serverPath, fileName + ext));

                    item.Url = virFolder + fileName + ext;

                    entities.MusicPages.Add(item);
                    entities.SaveChanges();
                    
                }
            }
        }