how to work with Checkboxlist in asp.net with 3 tier architecture?

<asp:CheckBoxList ID="CheckBoxList1" runat="server">
	<asp:ListItem>Playing Cricket</asp:ListItem>
	<asp:ListItem>Reading</asp:ListItem>
	<asp:ListItem>Browsing</asp:ListItem>
</asp:CheckBoxList>

foreach(ListBox li in CheckBoxList1.Items)
{
    if(li.SelectedItem)
    {
    }
}

protected void btnsave_Click(object sender, EventArgs e)
{
    clsbo objbo = new clsbo();
    objbo.Name = TextBox1.Text.ToString();
    objbo.Department = DropDownList1.SelectedItem.Text.ToString();
    objbo.Gender = RadioButtonList1.SelectedItem.Text.ToString();

    string ext = System.IO.Path.GetExtension(FileUpload1.PostedFile.FileName);
    string[] validFileTypes = { "doc", "docx" };
    bool isValidFile = false;
    try
    {
        for (int i = 0; i < validFileTypes.Length; i++)
        {
            if (ext == "." + validFileTypes[i])
            {
                isValidFile = true;
                break;
            }
        }
        if (!isValidFile) //checking whether the file is valid or not
        {
            lbldisplay.ForeColor = System.Drawing.Color.Red;
            lbldisplay.Text = "Invalid File. Only " +
            string.Join(",", validFileTypes) + " files are allowed..";
            return;
        }
        foreach (ListBox li in CheckBoxList1.Items)
        {
            if (li.SelectedItem)
            {

            }
        }
    }
}

namespace BLL
{
    public class clsbll
    {
        public void insertdetails(clsbo objbo)
        {
            clsbll objbll = new clsbll();
            objbll.insertdetails(objbo);
        }
    }
}

namespace DAL
{
    public class clsdal
    {
        public void insertdata(clsbo objbo)
        {
            string cs = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
            using (SqlConnection con = new SqlConnection(cs))
            {
                using (SqlCommand cmd = new SqlCommand("insertvwtblregistration", con))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                    SqlParameter nameParameter = new SqlParameter
                    {
                        ParameterName = "@Name",
                        Value = objbo.Name
                    };
                    cmd.Parameters.Add(nameParameter);
                    SqlParameter departmentParameter = new SqlParameter
                    {
                        ParameterName = "@Department",
                        Value = objbo.Department
                    };
                    cmd.Parameters.Add(departmentParameter);
                    SqlParameter HobbiesParameter = new SqlParameter
                    {
                        ParameterName = "@Hobbies",
                        Value = objbo.Hobbies
                    };
                    cmd.Parameters.Add(HobbiesParameter);
                    SqlParameter GenderParameter = new SqlParameter
                    {
                        ParameterName = "@Gender",
                        Value = objbo.Gender
                    };
                    cmd.Parameters.Add(GenderParameter);
                    SqlParameter FileuploadParameter = new SqlParameter
                    {
                        ParameterName = "@Fileupload",
                        Value = objbo.Fileupload
                    };
                    cmd.Parameters.Add(FileuploadParameter);
                    con.Open();
                    cmd.ExecuteNonQuery();
                }
            }
        }
    }
}

public class clsbo
{
    private int _Id;
    private string _Name;
    private string _Gender;
    private string _Department;
    private string _Hobbies;
    private string _Fileupload;
    public int Id
    {
        set { _Id = value; }
        get { return _Id; }
    }
    public string Name
    {
        set { _Name = value; }
        get { return _Name; }
    }
    public string Gender
    {
        set { _Gender = value; }
        get { return _Gender; }
    }
    public string Department
    {
        set { _Department = value; }
        get { return _Department; }
    }
    public string Hobbies
    {
        set { _Hobbies = value; }
        get { return _Hobbies; }
    }
    public string Fileupload
    {
        set { _Fileupload = value; }
        get { return _Fileupload; }
    }
}