private void AddChildClick(object sender, RoutedEventArgs e)
        {
            string tmp      = "";
            int    count_ec = 0;

            try
            {
                bool check1 = first_NameTextBox.Text.Any(who => char.IsLetter(who));
                if (first_NameTextBox.Text != null)
                {
                    if (!check1)
                    {
                        first_NameTextBox.BorderBrush = Brushes.Red;
                        tmp += "Invalid First name! \n";
                        first_NameTextBox.Text = "";
                        count_ec++;
                    }
                }

                if ((DateTime)dateDatePicker.SelectedDate >= (DateTime.Today))
                {
                    tmp += "Invalid Date!";
                    count_ec++;
                }

                bool check = iDTextBox.Text.Any(who => !char.IsLetter(who));
                if ((iDTextBox.Text != null) && (iDTextBox.Text != "0"))
                {
                    if (!check)
                    {
                        iDTextBox.BorderBrush = Brushes.Red;
                        tmp           += "Invalid ID Number! \n";
                        iDTextBox.Text = "";
                        count_ec++;
                    }
                }

                if (count_ec != 0)
                {
                    throw new Exception(tmp);
                }

                else
                {
                    bl.Add_Chaild(child);
                    MessageBox.Show("Add child successful");
                    child            = new BE.Child();
                    this.DataContext = child;
                    Close();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                first_NameTextBox.BorderBrush = Brushes.Black;
                iDTextBox.BorderBrush         = Brushes.Black;
            }
        }