<%@ Control Language="C#" AutoEventWireup="true" %>
<%@ Import Namespace="System.Linq" %>

<script runat="server" language="C#">
 private int _addressTypeId = 0;
    public int AddressTypeId
        {
        get
            {
            return int.Parse(ddlAddressType.SelectedValue);
            }
        set
            {
            _addressTypeId = value;
            }
        }

    protected void Page_Load(object sender, EventArgs e)
        {

        }

    protected void ddlAddressType_DataBound(object sender, EventArgs e)
        {
        if (_addressTypeId != 0)
            {
            System.Web.UI.WebControls.ListItem li = ddlAddressType.Items.FindByValue(_addressTypeId.ToString ());
            if (li != null)
                li.Selected = true;
            }
        }
</script>
<asp:LinqDataSource ID="lnqAddressType"  runat="server" 
    ContextTypeName="WEBSWAPP.Website.Data.SamplesDataContext" 
    Select="new (Name, Id)" TableName="AddressTypes"></asp:LinqDataSource>
<asp:DropDownList ID="ddlAddressType" runat="server"  OnDataBound="ddlAddressType_DataBound"
    DataSourceID="lnqAddressType" DataTextField="Name" DataValueField="Id" ></asp:DropDownList>