How to insert data in 3 tier architecture

#region InsertData
   public int Insert(NCBAL ObjInsert)
   {
       con = new SqlConnection(constr);
       con.Open();
       cmd = new SqlCommand("InsertNewComp_SP", con);
       cmd.CommandType = CommandType.StoredProcedure;
       try
       {
           cmd.Parameters.AddWithValue("@compliantID",ObjInsert.compid).ToString();
           cmd.Parameters.AddWithValue("@customerid", ObjInsert.cusid).ToString();
           cmd.Parameters.AddWithValue("@customername", ObjInsert.cusname).ToString();
           cmd.Parameters.AddWithValue("@branchid", ObjInsert.ddlbranch).ToString();
           cmd.Parameters.AddWithValue("@servicetype",ObjInsert.servicetype);
           return cmd.ExecuteNonQuery();
       }
       catch
       {
           throw;
       }
       finally
       {
           cmd.Dispose();
           con.Close();
           con.Dispose();
       }
   }
   #endregion

#region Insert Data
   public int Insert(NCBAL ObjInsert)
   {
       try
       {
           return ncd.Insert(ObjInsert);
       }
       catch
       {
           throw;
       }
       finally
       {
           ncd = null;
       }
   }
   #endregion

ncb.compid = txtcompid.Text;
                        ncb.cusid = txtcusid.Text;
                        ncb.cusname = txtcusname.Text;
                        ncb.cusnum = txtcusnumber.Text;
                        ncb.compname = txtcompname.Text;
                        ncb.ddlproduct = DDlProductname.Text;
                        ncb.compliant = txtCompliant.Text;
                        ncb.compdate = Convert.ToDateTime(txtcompdate.Text);
                        ncb.solution = txtsolution.Text;
                        ncb.ddlassign = DDlAssign.Text;
                        ncb.datetocomp = Convert.ToDateTime(txtdatetocom.Text);
                        ncb.ddlpriorty = DDlPriorty.Text;
                        ncb.ddlstatus = DDlStatus.Text;
                        ncb.complianttime = txtcomplianttime.Text;
                        ncb.datetocomp = txtdatecomptime.Text;
                        ncb.ddlbranch = DDLbranch.Text;
                        String str = "";
                        for (int i = 0; i <= CBLservicetype.Items.Count - 1; i++)
                        {
                            if (CBLservicetype.Items[i].Selected)
                            {
                                if (str == "")
                                {
                                    str = CBLservicetype.Items[i].Text;
                                }
                                else
                                {
                                    str += "," + CBLservicetype.Items[i].Text;
                                }
                            }
                        }
                        ncb.servicetype = str;
                    }