Filter GridView using multiple CheckBoxLists in ASP.Net

Hello,

Here i have used GridView with Two Checkbox list one for Country and Other for ContactTitle and i am fetching data from Customers Table (Northwind Database).

firstly data will be get in this manner  

SELECT CustomerID,CompanyName,ContactTitle,Address,Country,ContactTitle FROM Customers

then if i check the chkType first time then there will not be any changes becouse its in the And Condition and i have written code like that if we check country and then check the chkType then gridview will be changed

HTML: 

<form id="form1" runat="server">
    <div>
        Check Countries
        <asp:CheckBoxList ID="chkCountries" runat="server" AutoPostBack="true" OnSelectedIndexChanged="Counrty_Selected">
            <asp:ListItem Text="Germany" />
            <asp:ListItem Text="Spain" />
            <asp:ListItem Text="USA" />
        </asp:CheckBoxList>
        <br />
        Check Type
        <asp:CheckBoxList ID="chlType" runat="server" AutoPostBack="true" OnSelectedIndexChanged="Type_Selected">
            <asp:ListItem Text="Owner" />
            <asp:ListItem Text="Sales representative" />
            <asp:ListItem Text="Order Administrator" />
        </asp:CheckBoxList>
        <br />
        GridView:
        <asp:GridView ID="gvDemo" AutoGenerateColumns="false" PageSize="10" AllowPaging="true"
            OnPageIndexChanging="gvDemo_PageIndexChanging" runat="server" Width="500">
            <Columns>
                <asp:BoundField DataField="CustomerID" HeaderText="CustomerID" />
                <asp:BoundField DataField="CompanyName" HeaderText="CompanyName" />
                <asp:BoundField DataField="ContactTitle" HeaderText="ContactTitle" />
                <asp:BoundField DataField="Address" HeaderText="Address" />
                <asp:BoundField DataField="Country" HeaderText="Country" />
                <asp:BoundField DataField="ContactTitle" HeaderText="ContactTitle" />
            </Columns>
        </asp:GridView>
    </div>
    </form>

C#:

 protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                this.BindList();
            }
        }

        protected void gvDemo_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            gvDemo.PageIndex = e.NewPageIndex;
            BindList();
        }

        private void BindList()
        {
            string conString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
            string query = "SELECT CustomerID,CompanyName,ContactTitle,Address,Country,ContactTitle FROM Customers";
            string condition = string.Empty;
            foreach (ListItem item in chkCountries.Items)
            {
                condition += item.Selected ? string.Format("'{0}',", item.Value) : "";
            }
            if (!string.IsNullOrEmpty(condition))
            {
                condition = string.Format(" where Country in ({0})", condition.Substring(0, condition.Length - 1));
            }
            string condition2 = string.Empty;
            foreach (ListItem item in chlType.Items)
            {
                condition2 += item.Selected ? string.Format("'{0}',", item.Value) : "";
            }
            if (!string.IsNullOrEmpty(condition2))
            {
                condition2 = string.Format(" AND ContactTitle in ({0})", condition2.Substring(0, condition2.Length - 1));
            }
            SqlCommand cmd = new SqlCommand(query + condition + condition2); using (SqlConnection con = new SqlConnection(conString))
            {
                using (SqlDataAdapter sda = new SqlDataAdapter())
                {
                    cmd.Connection = con; sda.SelectCommand = cmd;
                    using (DataSet ds = new DataSet())
                    {
                        sda.Fill(ds);
                        gvDemo.DataSource = ds;
                        gvDemo.DataBind();
                    }
                }
            }
        }
        protected void Counrty_Selected(object sender, EventArgs e)
        {
            this.BindList();
        }
        protected void Type_Selected(object sender, EventArgs e)
        {
            foreach (ListItem item in chkCountries.Items)
            {
                if (item.Selected == true)
                {
                    this.BindList();
                }
            }   
        }
    }