AjaxControlToolkit问题

[messiahke]

1.我用了 AsyncFileUpload 之后VS输出里面就出现了
g.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(4047:12) : 需要对象
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(4049:12) : 需要对象
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(4050:12) : 需要对象
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(4051:12) : 需要对象
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(4052:12) : 需要对象
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(4053:12) : 需要对象
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(4054:12) : 需要对象
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(812:51) : 对象不支持此属性或方法
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(814:8) : 需要对象
Javascript Intellisense Message: MicrosoftAjax.debug.js:AjaxControlToolkit, Version=4.1.51116.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e(3973:4) : Sys.ArgumentUndefinedException: undefined

我的部分代码是：
<%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="asp" %>


<asp:ScriptManager ID="scriptmanager1" runat="server"></asp:ScriptManager>
<asp:AsyncFileUpload ID="fu_teacher" runat="server" OnUploadedComplete="fu_teacher_UploadedComplete" PersistFile="True" />
用一般能正常用 就是偶尔弹出为应用实例的错误。。请问这是为什么

2.还有就是问一下 有没有办法让这个控件不会因为页面刷新内容变空