private void btnEdit_Click(object sender, RoutedEventArgs e)
        {
            ServiceTypeModel stm = dgvServiceType.SelectedItem as ServiceTypeModel;

            if (stm != null)
            {
                ServiceTypeDetails std = new ServiceTypeDetails(this, stm);
                std.ShowDialog();
            }
            else
            {
                MessageBox.Show("No record selected.");
            }
        }
        private void btnAdd_Click(object sender, RoutedEventArgs e)
        {
            ServiceTypeDetails std = new ServiceTypeDetails(this);

            std.ShowDialog();
        }