Untitled

private void btnArv_Click(object sender, EventArgs e)
{
    summa arvu = new summa();
    // Õige
    try
    {
        arvu.number1 = Convert.ToSingle(txtArv1.Text);
        arvu.number2 = Convert.ToSingle(txtArv2.Text);
        if (chkTehing.Checked)
        {
            arvu.tehing = "*";
            chkTehing.Text = "Liida";
        }
        else
        {
            arvu.tehing = "+";
            chkTehing.Text = "Lahuta";
        }
        // Tulemus
        Single tulemus = arvu.arvutus();
        lblSumma.Text = Convert.ToString(arvu.number1) + arvu.tehing
            + Convert.ToString(arvu.number2) + " = " + Convert.ToString(tulemus);
    }
    // Vale
    catch
    {
        lblSumma.Text = "";
        MessageBox.Show("Sisesta arvu", "Viga",
            MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}