Text Box(multiple checked checkbox value displayed at a time in text box)

HTML:


for popup extender control paste this after <%@page....%>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
and
paste this inside contentplaceholder1
<asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>

 <div>
                                <asp:TextBox ID="txtGuest" runat="server"></asp:TextBox>
                                <asp:PopupControlExtender ID="txtGuest_PopupControlExtender" runat="server" DynamicServicePath=""
                                    Enabled="True" ExtenderControlID="" TargetControlID="txtGuest" PopupControlID="Panel1"
                                    OffsetY="22">
                                </asp:PopupControlExtender>
                                <asp:Panel ID="Panel1" runat="server" Style="display: none; background-color: #F2F2F2;
                                    border-style: solid; border-width: 1px; overflow: auto; top: 0; visibility: visible;
                                    width: 306px; z-index: 1000;">
                                    <asp:CheckBoxList ID="chkLGuest" runat="server" DataTextField="Name" DataValueField="Id"
                                        AutoPostBack="True" OnSelectedIndexChanged="chkLGuest_SelectedIndexChanged">
                                    </asp:CheckBoxList>
                                </asp:Panel>
                            </div>


c# code:

load check box :
chkLGuest.DataSource = new GuestManager().GetAllGuests();
        chkLGuest.DataBind();

protected void chkLGuest_SelectedIndexChanged(object sender, EventArgs e)
    {
        string name = "";
        for (int i = 0; i < chkLGuest.Items.Count; i++)
        {
            if (chkLGuest.Items[i].Selected)
            {
                name += chkLGuest.Items[i].Text + ",";
            }
        }
        txtGuest.Text = name;
    }


similarly for guestId we use item.selected.