Refresh Listview data based on Selection of a Dropdown

Question

Hello, 


    I am using aSP.net 4.5 Web Forms. I have a listview whose SelectMethod is set. In the header of ListView I have a dropdown whose data is populated dynamically & set Datasource.
Now, based on the selection of drop down I want to show items in ListView. I am not able to get this part. Here's my code :

        <asp:ListView id="ListView1" runat="server"

            DataKeyNames="ChannelId" 

ItemType="VincitoreCRMApplication.Models.ChannelViewModel" SelectMethod="GetData" >

            <LayoutTemplate>

                <table class="table" runat="server">

                    <tr runat="server">

                        <td runat="server">

                            <table id="itemPlaceholderContainer" runat="server" class="table">

                                <thead>

                                        <th>

           <asp:LinkButton Text="Country" CommandName="Sort" CommandArgument="Country" runat="Server" />

                                            <br />

                                            <asp:DropDownList ID="CountryList" runat="server" AutoPostBack="true" OnSelectedIndexChanged="CountryList_SelectedIndexChanged" >

                                            </asp:DropDownList>

           </th>

                                        <th>&nbsp;</th>

                                    </tr>

                                </thead>

In the code behind :

        protected void Page_Load(object sender, EventArgs e)

        {

            if (!IsPostBack)

            {
                // Populate DropDown Countries

                DropDownList CountryList = ListView1.FindControl("CountryList") as DropDownList;

                if (CountryList != null)

                {

                    CountryList.DataSource = GetCountries();

                    CountryList.DataBind();

                    CountryList.SelectedIndex = -1;

                }

            }

           

        }

       // Model binding method to get List of Channel entries

        // USAGE: <asp:ListView SelectMethod="GetData">

        public IQueryable<VincitoreCRMApplication.Models.ChannelViewModel> GetData()

        {

            return _db.Channels

                 .Select(u => new ChannelViewModel

                 {

                     ChannelId = u.ChannelId,

                     NameSuffix = u.NameSuffix,

                     FirstName = u.FirstName,

                     LastName = u.LastName,

                     City = u.City,

                     State = u.State,

                     Country = u.Country

                 });

            //return _db.Channels;            

        }

        public string[] GetCountries()

        {

            List<String> list = GetData().Select(o => o.Country).Distinct().ToList<String>();

            list.Insert(0, "--- Filter ---");

            list.RemoveAll(s => s == null);

            return list.ToArray();  

        }

        // Selection Event of CountryList DropDown
        protected void CountryList_SelectedIndexChanged(object sender, EventArgs e)

        {

            DropDownList CountryList = ListView1.FindControl("CountryList") as DropDownList;

            if (CountryList != null)

            {

                System.Diagnostics.Debug.WriteLine("Selected Index = " + CountryList.SelectedIndex);

                if (CountryList.SelectedIndex > -1)
                    // This also gives proepr result

                    System.Diagnostics.Debug.WriteLine("Selected text = " + CountryList.Text);

            }

        }

Now the only part I am stuck is, how do I refresh the GetData() using the selected Country from drop down. If I set a parameter in GetData, then how do I pass parameter in SelectMethod part.

I believe I can set the DataSource and Databind of ListView programmatically & get it work. But I think using Model Binding is more worth than using DataSource/Databind pattern. 
Also, I wont be adding/Editing/Deleting items in the Lsitview - it is just for display & viewing with a facility to filter the data based on selection.

Can anyone please suggest me for the above. I am not able to get any expected result from googling the same.

Kindly try to help me at the earliest.

Thanks