private void button1_Click(object sender, EventArgs e)
{
int penNumber, penCap, petNumber, clinicNumber;
string petComments;
DateTime DateIN, DateOUT;
penNumber = Convert.ToInt32(cmbPenNumber.SelectedValue.ToString());
penCap = 4;
petNumber = Convert.ToInt32(txtPNum.Text);
petComments = rtbComments.Text;
DateIN = dateTimePicker1.Value;
DateOUT = dateTimePicker2.Value;
clinicNumber = Convert.ToInt32(cmbClinicNumber.SelectedValue.ToString());
database.BookPen(penNumber, penCap, penStatus, petNumber, petComments, DateIN, DateOUT, clinicNumber);
this.Close();
}