急，关于自定义验证控件的问题！

这是我的关于一个自定义验证控件的程序：
<%@ Page Language="C#" Debug="true" %>
<%@ import Namespace="System.Data" %>
<%@ import Namespace="System.Data.OleDb" %>
<script runat="server">
    
    void CustomValidator1_ServerValidate(object sender, ServerValidateEventArgs e)
    {
      int num =Int32.Parse(Args.Value);
      if(num%2==0)
       {
         Args.IsValid=true;return;
       }
       Args.IsValid=false;
    }
    
    void Button1_Click(object sender, EventArgs e)
     {
      if(Page.IsValid)
       {
        Lable1.Text="输入数据是："+TextBox1.Text;
       }
    
     }</script>
<html>
<head>
</head>
<body>
    <form runat="server">
        <table height="90" width="500" align="center">
            <tbody>
                <tr>
                    <td>
                        <asp:Label id="Label1" runat="server" borderstyle="Dotted" font-size="Small" font-names="楷体_GB2312">使用CustomValidator数据验证控件</asp:Label></td>
                </tr>
                <tr>
                    <td>
                        <asp:Label id="Label2" runat="server">请输入一个偶数：</asp:Label>
                        <asp:TextBox id="TextBox1" runat="server" MaxLength="20"></asp:TextBox>
                        <asp:CustomValidator id="CustomValidator1" runat="server" OnServerValidate="CustomValidator1_ServerValidate" ErrorMessage="必须输入偶数"></asp:CustomValidator>
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Button id="Button1" onclick="Button1_Click" runat="server" Text="提交"></asp:Button>
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label id="Label3" runat="server"></asp:Label></td>
                </tr>
            </tbody>
        </table>
        <!-- Insert content here -->
    </form>
</body>
</html>
提示错误：Compiler Error Message: CS0246: The type or namespace name 'Args' could not be found (are you missing a using directive or an assembly reference?)
int num =Int32.Parse(Args.Value);——这一行出错