ActionListener al;
al = new ActionListener()
    {
    public void actionPerformed(ActionEvent ae)
        {
            try
            {
                double value = Double.parseDouble(
                    txtDegrees.getText());
                double result = (value-32.0)*5.0/9.0;
                lblResult.setText("Celsius = "+result);
            }
            catch (NumberFormatException nfe)
            {
                JOptionPane.showMessageDialog(
                    null, "Bad input");
            }
        }
    };

final JButton btnToC = new JButton("To Celsius");
btnToC.addActionListener(al);

Button btnToC = new Button();
btnToC.Text = "To Celsius";
btnToC.Location = new Point(
    ANCHORX,
    lblResult.Location.Y+lblResult.Height*2);
btnToC.Size = btnToC.PreferredSize;
btnToC.Click += new EventHandler(btnToC_Click);
// skipping a few lines
public void btnToC_Click(object ob, EventArgs e)
{
    double degrees = 0.0;

    try
    {
        degrees = Double.Parse(txtDegrees.Text);
    }
    catch (Exception)    // Unlike Java, an exception 
                        // variable is not needed if
                        // it will not be used by the 
                        // exception handler.
    {
        MessageBox.Show("Bad input", 
            "Tempverter", MessageBoxButtons.OK, 
            MessageBoxIcon.Exclamation);
        return;
    }

    lblResult.Text = "Celsius = "+((degrees-32.0)*5.0/9.0);
}