private void AddConferenceButton_Click(object sender, EventArgs e)
        {
            formDTO.op = CrudOpr.Create;
            CreateUpdateParticipantForm form = new CreateUpdateParticipantForm(this, formDTO);

            form.Show();
        }
        private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            int id = Convert.ToInt32(dataGridView1.CurrentRow.Cells["participantIdDataGridViewTextBoxColumn"].Value);

            // updating
            if (e.ColumnIndex == 9)
            {
                formDTO.op = CrudOpr.Update;

                ViewConferencesWithParticipant findParticipant = dataFormDTO.db.ViewConferencesWithParticipants.SingleOrDefault(o => o.participantId == id);
                formDTO.obj = findParticipant;

                CreateUpdateParticipantForm form = new CreateUpdateParticipantForm(this, formDTO);
                form.Show();
            }

            // deleting
            if (e.ColumnIndex == 10)
            {
                // Запрашиваем подтверждение
                string message = "Do you want to delete?";
                string caption = "Y/n";
                var    result  = MessageBox.Show(message, caption,
                                                 MessageBoxButtons.YesNo,
                                                 MessageBoxIcon.Question);
                if (result == DialogResult.Yes)
                {
                    participant participant = new participant();
                    participant.participantId = id;
                    // deleting
                    if (crud.delete(participant))
                    {
                        MessageBox.Show("Conference was deleted!");
                        resetData();
                    }
                    else
                    {
                        MessageBox.Show("Deleting was denied");
                    }
                }
            }
        }