HELP!!!!!!a problem of using asp.net build mobile site

the code is simple

 page  test4.aspx:

     <%@ Page Language="C#" AutoEventWireup="true" CodeFile="test4.aspx.cs" Inherits="test4" %>
<%@ Register TagPrefix="mobile" Namespace="System.Web.UI.MobileControls" Assembly="System.Web.Mobile" %>

<html xmlns="http://www.w3.org/1999/xhtml" >
<body>
    <mobile:Form id="Form1" runat="server">
        <mobile:TextBox ID="TextBox1" Runat="server">
        </mobile:TextBox>
        <mobile:Command ID="Command1" Runat="server" OnClick="Command1_Click">Command </mobile:Command>

    </mobile:Form>
</body>
</html>


behind c ...