Need To Cache Or Store These SqlDataSource Objects

I have the following:
omegalove.com

If you go to the search portion u will notice that
there are three dropdownlist that are populate using sqldatasource object.
I do not want these two post back. Is there a way we can cache this so it is faster.
I would like to learn. I appreciate any help. Please don't give me links. I much rather learn from someone who has hands on.
Thank you

I will have to separate the code from the ui?---------------------------------------------------------------------
Country:<asp:Image ID="FlagImg" runat="server" Height="12px" Width="20px" />

<asp:DropDownList ID="ddlCountry" runat="server" DataSourceID="SqlDSCountry" DataTextField="Country"

DataValueField="CountryID" AutoPostBack="True" OnDataBound="ddlCountry_DataBound" OnSelectedIndexChanged="ddlCountry_SelectedIndexChanged">

</asp:DropDownList>

<asp:SqlDataSource ID="SqlDSCountry" runat="server" ConnectionString="<%$ ConnectionStrings:omegaloveConnectionString %>"

SelectCommand="SELECT [CountryID], [Country] FROM [CountryCodes] ORDER BY [Country]">

</asp:SqlDataSource>


----------------------------------------------------------
State/Province:<br />

<asp:DropDownList ID="ddlRegion" runat="server" AutoPostBack="True"

DataSourceID="SqlDSRegion" DataTextField="Region" DataValueField="RegionID" OnDataBound="ddlRegion_OnDataBound" OnSelectedIndexChanged="ddlRegion_SelectedIndexChanged">

</asp:DropDownList><asp:SqlDataSource ID="SqlDSRegion" runat="server" ConnectionString="<%$ ConnectionStrings:omegaloveConnectionString %>"

SelectCommand="SELECT [RegionID], [Region] FROM [SubCountryCode] WHERE ([CountryID] = @CountryID)">

<SelectParameters>

<asp:ControlParameter ControlID="ddlCountry" Name="CountryID" PropertyName="SelectedValue"

Type="String" />

</SelectParameters>

</asp:SqlDataSource>
---------------------------------------------------------------
City :<br />

<asp:DropDownList ID="ddlCity" runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlCity_SelectedIndexChanged" DataSourceID="DSCity" DataTextField="City" DataValueField="City">

</asp:DropDownList>

<asp:SqlDataSource ID="DSCity" runat="server" ConnectionString="<%$ ConnectionStrings:omegaloveConnectionString %>"

SelectCommand="SELECT [City] FROM [WorldCities] WHERE (([CountryID] = @CountryID) AND ([RegionID] = @RegionID))">

<SelectParameters>

<asp:ControlParameter ControlID="ddlCountry" Name="CountryID" PropertyName="SelectedValue" Type="String" />

<asp:ControlParameter ControlID="ddlRegion" Name="RegionID" PropertyName="SelectedValue" Type="String" />

</SelectParameters>

</asp:SqlDataSource>


---------------------------------------------------------------------------------------------------------------------------------------------------------------

This is my behind code.

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using OmegaLove;
using OmegaLove.UI;


namespace OmegaLove.UI.Controls
{
    public partial class Search : BaseWebPart
    {    

        protected void Page_Load(object sender, EventArgs e)
        {

        }

       


        protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)
        {
            FlagImg.ImageUrl = "../images/flags/" + ddlCountry.SelectedValue + ".gif";
            ResetRegion();
            ResetCity();

        }

        protected void ddlRegion_SelectedIndexChanged(object sender, EventArgs e)
        {
            ResetCity();
        }


        protected void ddlCountry_DataBound(object sender, EventArgs e)
        {
            ddlCountry.SelectedIndex = 39;
            FlagImg.ImageUrl = "../images/flags/" + ddlCountry.SelectedValue + ".gif";
        }

       

        protected void ddlRegion_OnDataBound(object sender, EventArgs e)
        {
            ResetCity();
        }


        private void ResetRegion()
        {
            ddlRegion.Items.Clear();
         //   ddlRegion.DataBind();

            if (ddlRegion.Items.Count == 0)
            {
                ListItem item = new ListItem("Not Available");
                ddlRegion.Items.Add(item);
            }
        }

        private void ResetCity()
        {
            ddlCity.Items.Clear();
        //    ddlCity.DataBind();

            if (ddlCity.Items.Count == 0)
            {
                ListItem item = new ListItem("Not Available");
                ddlCity.Items.Add(item);
            }
        }


        protected void ddlCity_SelectedIndexChanged(object sender, EventArgs e)
        {

        }
}
}