Implementing the Observer Pattern

<%@ Control Language="C#" AutoEventWireup="true" Inherits="ObserverTutorial.Address_UC" Codebehind="Address_UC.ascx.cs" %>
<%@ Register Src="RecordDetails_UC.ascx" TagName="RecordDetails_UC" TagPrefix="uc1" %>
<table width="100%" border="0" cellpadding="0" cellspacing="0">
    <tr>
        <td>
            <fieldset style="border-right: black 1px solid; border-top: black 1px solid; border-left: black 1px solid; border-bottom: black 1px solid">
                <legend style="border-right: black 1px solid; border-top: black 1px solid; border-left: black 1px solid; border-bottom: black 1px solid">
                    <asp:Label ID="lblContactAddressDetails" runat="server" Text="Address Details"></asp:Label></legend>
                <table style="width: 100%">
                    <tr>
                        <td class="data">
                            <asp:Label ID="lblCountryName" runat="server" CssClass=" " Text="Country Name"></asp:Label></td>
                        <td class="data">
                            <asp:TextBox ID="txtCountry" runat="server" CssClass="txt" Width="160px"></asp:TextBox></td>
                        <td class="data"  >
                            <asp:Label ID="lblCityName" runat="server" Text="City Name"></asp:Label></td>
                        <td class="data">
                            <asp:TextBox ID="txtCity" runat="server" CssClass="txt" Width="160px"></asp:TextBox></td>
                    </tr>
                    <tr>
                        <td class="data">
                            <asp:Label ID="lblPostCode" runat="server" Text="Postal Code" CssClass=" "></asp:Label></td>
                        <td class="data">
                            <asp:TextBox ID="txtPostalCode" runat="server" CssClass="txt" Width="160px"></asp:TextBox></td>
                        <td class="data"  >
                            <asp:Label ID="lblState" runat="server" Text="State"></asp:Label></td>
                        <td class="data">
                            <asp:TextBox ID="txtState" runat="server" Width="160px" CssClass="txt"></asp:TextBox></td>
                    </tr>
                    <tr>
                        <td class="data" style="width: 130px">
                            <asp:Label ID="lblStreet" runat="server" Text="Street" CssClass=" "></asp:Label></td>
                        <td class="data">
                            <asp:TextBox ID="txtStreet" runat="server" Width="160px" CssClass="txt"></asp:TextBox></td>
                        <td class="data" >
                            <asp:Label ID="lblBuilding" runat="server" Text="Building"></asp:Label></td>
                        <td class="data">
                            <asp:TextBox ID="txtBuilding" runat="server" Width="160px" CssClass="txt"></asp:TextBox></td>
                    </tr>
                    <tr>
                        <td class="data" style="width: 130px">
                            <asp:Label ID="lblAddressId" runat="server" CssClass=" " Text="Address Id"></asp:Label></td>
                        <td class="data">
                            <asp:TextBox ID="txtAddressId" runat="server" CssClass="txt" Width="160px"></asp:TextBox></td>
                        <td class="data">
                        </td>
                        <td class="data">
                        </td>
                    </tr>
                </table>
            </fieldset>
            <uc1:RecordDetails_UC id="RecordDetails_UC1" runat="server">
            </uc1:RecordDetails_UC></td>
    </tr>
    <tr>
        <td>
            &nbsp;&nbsp;
            <asp:Button ID="btnReset" runat="server" CssClass="btn" Text="Reset" />
            &nbsp;
            <asp:Button ID="btnSave" runat="server" CssClass="btn" Text="Save" OnClick="btnOk_Click" /></td>
    </tr>
</table>