Repeater中使用Button

<asp:Repeater ID="Repeater3" runat="server">
            <ItemTemplate>
                <div class="line_item" ><a href="line.aspx?line_id=<%#Eval("id") %>"><%#Eval("title") %></a><span style="color: rgb(136, 136, 136); float: right; margin-right: 90px;"><%#Eval("price") %>元/人</span>
                    <asp:HiddenField ID="lineId" runat="server" Value='<%#Eval("id")%>' />
                <asp:Button ID="Button1" OnClick="Advance"  style="float: right; margin-right: -120px; margin-top: -4px;" runat="server" Text="预定" /></div>
            </ItemTemplate>
        </asp:Repeater>

#region 预定
    protected void Advance(object sender, EventArgs e) {
        Button bt = sender as Button;
        RepeaterItem ri = bt.Parent as RepeaterItem;
        HiddenField tx = ri.FindControl("lineId") as HiddenField;
        if (!object.Equals(tx, null)) 
        { Response.Write(tx.Value); }
    }
    #endregion