Как заполнить поле в таблице datagrid combobox`ом в WPF

как заполнить таблицу combobox`ом, чтобы выбранные значения из комбобокса записывались в таблицу

прикладываю фрагмент кода, сделано на WPF

    SqlDataAdapter adapter1;

    DataTable RouteTable1;
    string connectionString1;

    private class ListOP
    {
        public string PointList { get; set; }
    }


    private List<string> PointsList = new List<string>();
    public RouteTable()
    {
        InitializeComponent();
        connectionString1 = "Data Source=DBSrv\\SQL2021;Initial Catalog = !007ca2ArestovTyrPoxod;Integrated Security = True";
    }
    private void RouteLoaded(object sender, RoutedEventArgs e)
    {
        
        RouteTable1 = new DataTable();
        DataSet RouteTable1DataSet = new DataSet();

        SqlConnection connection = null;
        
        try
        {
            

            string sql = "SELECT * FROM Название_Маршрута";
            connection = new SqlConnection(connectionString1);
            SqlCommand command = new SqlCommand(sql, connection);
            adapter1 = new SqlDataAdapter(command);
            

            adapter1.InsertCommand = new SqlCommand("sp_InsertRoute1", connection);
            adapter1.InsertCommand.CommandType = CommandType.StoredProcedure;
            SqlParameter parameter = adapter1.InsertCommand.Parameters.Add("@Id", SqlDbType.Int, 0, "ID_Маршрута");
            adapter1.InsertCommand.Parameters.Add(new SqlParameter("@Type", SqlDbType.NVarChar, 40, "Вид_Отдыха"));
            adapter1.InsertCommand.Parameters.Add(new SqlParameter("@Title", SqlDbType.NVarChar, 40, "Название"));
            adapter1.InsertCommand.Parameters.Add(new SqlParameter("@Country", SqlDbType.NVarChar, 40, "Страна"));
            adapter1.InsertCommand.Parameters.Add(new SqlParameter("@Duration", SqlDbType.Int, 0, "Длительность"));
            adapter1.InsertCommand.Parameters.Add(new SqlParameter("@Difficult", SqlDbType.NVarChar, 40, "Сложность"));
            

            string sqlS = "SELECT Название_Точки FROM Точки_Остановки";
            
            connection = new SqlConnection(connectionString1);
            connection.Open();
            SqlCommand command1 = new SqlCommand(sqlS, connection);
            SqlDataReader reader = command1.ExecuteReader();
            if (reader.HasRows)
            {
                while (reader.Read())
                {
                    PointsList.Add(reader.GetString(0));
                    
                }
            }
            
            
            parameter.Direction = ParameterDirection.Output;

            //adapter1.Fill(RouteTable1DataSet, "test");
            adapter1.Fill(RouteTable1);
            RouteGrid.ItemsSource = RouteTable1.DefaultView;
            //RouteGrid.ItemsSource = RouteTable1DataSet.Tables["test"].AsEnumerable();
            PointsCombo.ItemsSource = PointsList;
            
            

        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);

        }
        finally
        {
            if (connection != null)
                connection.Close();
        }