private void btnAddGuest_Click(object sender, EventArgs e)
        {
            this.Close();
            frm_AddEditGuest theFrmAddEditGuest = new frm_AddEditGuest();

            theFrmAddEditGuest.Show();
        }
 private void btnEditGuest_Click(object sender, EventArgs e)
 {
     if (dgvGuests.SelectedRows.Count > 0)
     {
         frm_AddEditGuest theFrmAddEditGuest = new frm_AddEditGuest(true, dgvGuests.SelectedRows[0].Cells[0].Value.ToString());
         this.Close();
         theFrmAddEditGuest.Show();
     }
     else
     {
         MessageBox.Show("Proszę zaznaczyć gościa na liście!", "Błąd", MessageBoxButtons.OK, MessageBoxIcon.Error);
     }
 }