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

<script runat="server" language="C#">
    private int _cityId = 0;
    private int _countryId = 0;
    private int _provinceId = 0;
    private  WEBSWAPP.Website.Data.SamplesDataContext  db;
    public int CityId
        {
        get
            {

            return int.Parse(ddlCity.SelectedValue);
            }
        set
            {
            _cityId = value;
            db = new WEBSWAPP.Website.Data.SamplesDataContext();
            var city = db.Locations.Where(l => l.Id == _cityId).Single();
            if (city != null)
                {
                _provinceId = city.Location1.Id;
                _countryId = city.Location1.Location1.Id;

                }

            }
        }
    protected void Page_Load(object sender, EventArgs e)
        {

        }

    protected void ddlCountry_DataBound(Object sender, EventArgs e)
        {
        if (_countryId != 0)
            {
            System.Web.UI.WebControls.ListItem li = ddlCountry.Items.FindByValue(_countryId.ToString());
            if (li != null) li.Selected = true;
            }
        }
    protected void ddlProvince_DataBound(object sender, EventArgs e)
        {
        if (_provinceId != 0)
            {
            System.Web.UI.WebControls.ListItem li = ddlProvince.Items.FindByValue(_provinceId.ToString());
            if (li != null) li.Selected = true;
            }
        ddlCity.DataBind();
        }
    protected void ddlCity_DataBound(object sender, EventArgs e)
        {
        if (_cityId != 0)
            {
            System.Web.UI.WebControls.ListItem li = ddlCity.Items.FindByValue(_cityId.ToString());
            if (li != null) li.Selected = true;
            }
        }
</script>
   <div>
        <asp:LinqDataSource ID="lnqCountry" runat="server" ContextTypeName="WEBSWAPP.Website.Data.SamplesDataContext"
            Select="new (Id, Name)" TableName="Locations" Where="TypeId == @TypeId">
            <WhereParameters>
                <asp:Parameter DefaultValue="1" Name="TypeId" Type="Int32" />
            </WhereParameters>
        </asp:LinqDataSource>
        <asp:DropDownList ID="ddlCountry" runat="server" DataSourceID="lnqCountry" DataTextField="Name"
            DataValueField="Id" AutoPostBack="true"  OnDataBound="ddlCountry_DataBound" Width="120px"
            >
        </asp:DropDownList>
        <asp:LinqDataSource ID="lnqProvince" runat="server" ContextTypeName="WEBSWAPP.Website.Data.SamplesDataContext"
            Select="new (Id, Name)" TableName="Locations" 
            Where="TypeId == @TypeId &amp;&amp; ParentId == @ParentId" >
            <WhereParameters>
                <asp:Parameter DefaultValue="2" Name="TypeId" Type="Int32" />
                <asp:ControlParameter ControlID="ddlCountry" Name="ParentId" 
                    PropertyName="SelectedValue" Type="Int32" />
            </WhereParameters>
        </asp:LinqDataSource>
        <asp:DropDownList ID="ddlProvince" runat="server" DataSourceID="lnqProvince" DataTextField="Name"
            DataValueField="Id" AutoPostBack="true" ondatabound="ddlProvince_DataBound"   Width="150px"
            >
        </asp:DropDownList>
        <asp:LinqDataSource ID="lnqCity" runat="server" 
            ContextTypeName="WEBSWAPP.Website.Data.SamplesDataContext" 
            Select="new (Id, Name)" TableName="Locations" 
            Where="TypeId == @TypeId &amp;&amp; ParentId == @ParentId">
            <WhereParameters>
                <asp:Parameter DefaultValue="3" Name="TypeId" Type="Int32" />
                <asp:ControlParameter ControlID="ddlProvince" Name="ParentId" 
                    PropertyName="SelectedValue" Type="Int32" />
            </WhereParameters>
        </asp:LinqDataSource>
        <asp:DropDownList ID="ddlCity" runat="server" DataSourceID="lnqCity" DataTextField="Name" Width="150px"
            DataValueField="Id" OnDataBound="ddlCity_DataBound"  >
        </asp:DropDownList>
    </div>