Repeater里switch的使用方法

这是ASPX里的代码
代码如下:
<asp:Repeater ID="OrderList" runat="server">
         <ItemTemplate>
          <%#this.info(Eval("id").ToString(), Eval("id").ToString())%>
         </ItemTemplate>
</asp:Repeater>

下面是CS里代码
代码如下:
protected void Page_Load(object sender, EventArgs e)
    {   
        .......
    ｝
protected string info(string id)
    {
        switch (num)
        {
            case "0":
                returnStr = "ID为0";
                break;
            case "1":
                returnStr = "ID为1";
                break;
            case "2":
                returnStr = "ID为2";
                break;
            case "3":
                returnStr = "ID为3";
                break;
            case "4":
                returnStr = "ID为3";
                break;
        }
        return returnStr;
    }