中继器在回发时丢失数据

中继器标记:

<asp:Repeater ID="stat_Rptr" runat="server">
                <ItemTemplate>
                    <asp:CheckBox ID="IsSelected_ChkBx" runat="server" Text='<%# Eval("Item") %>' />
                    &nbsp;<asp:TextBox ID="Value_TxtBx" runat="server"></asp:TextBox>
                    <asp:HiddenField ID="ID_HdnFld" runat="server" Value='<%# Eval("ID") %>' />
                </ItemTemplate>
                <SeparatorTemplate>
                    <br></br>
                </SeparatorTemplate>
            </asp:Repeater>

后台代码:

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            PopulateStatRptr();
        }
     }

    private void PopulateStatRptr()
    {
        SqlConnection conn;
        SqlCommand comm;
        SqlDataReader reader;
        string _connString = "Data Source=localhost''SqlExpress;Initial Catalog=MyDb;Integrated Security=True";
        conn = new SqlConnection(ConString);
        comm = new SqlCommand("SELECT ID, Item FROM Stats", conn);
        try
        {
            conn.Open();
            reader = comm.ExecuteReader();
            stat_Rptr.DataSource = reader;
            stat_Rptr.DataBind();
            reader.Close();
        }
        finally
        {
            conn.Close();
        }
    }