Re CheckBoxList

Question

Hi I am Insert Multiple validate CheckBoxList in sql 2005.I have problum this code...
pls help m...
using System;
using System.Data;
using System.Configuration;
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 System.Data.SqlClient;
using System.Data.SqlTypes;
public partial class _Default : System.Web.UI.Page
{
string Strlist, Strlist1;
protected void Page_Load(object sender, EventArgs e)
{
}
private bool validate()
{
int counter = 0;
foreach (ListItem li in checkBoxList1.Items)
{
if (li.Selected)
{
counter = counter + 1;
Strlist = Strlist + " " + li.Text;
}
}
if (counter > 2)
{
return false;
}
else
{
return true;
}
}
private bool validate1()
{
int counter = 0;
foreach (ListItem li in CheckBoxList2.Items)
{
if (li.Selected)
{
counter = counter + 1;
Strlist1 = Strlist1 + " " + li.Text;
}
}
if (counter > 2)
{
return false;
}
else
{
return true;
}
}
private bool check()
{
if (validate1())
{
return true;
}
else
{
return false;
}

if(validate())
{
return true;
}
else
{
return false;
}
}
protected void button1_Click(object sender, EventArgs e)
{
if (check())
{
string data = ConfigurationManager.ConnectionStrings["manoj"].ConnectionString;
SqlConnection con = new SqlConnection(data);
SqlCommand cmd = new SqlCommand("insert into tabn(Country,City)values(@Country,@City)", con);
cmd.Parameters.Add("@Country", SqlDbType.VarChar).Value = checkBoxList1.SelectedItem.ToString();
cmd.Parameters.Add("@City", SqlDbType.VarChar).Value = Strlist1;
cmd.Connection = con;
try
{
con.Open();
cmd.ExecuteNonQuery();
Response.Write(true);
}
catch (Exception ex)
{
throw ex;
}
}
else
{
Response.Write(false);
}
}
}
If We are not use validate then insert value bt we use validation then give me some error pls help me........