private void button1_Click(object sender, EventArgs e) { string f = side1.Text; string n = side2.Text; string d = side3.Text; try { if (f.Length != 0) { double q = double.Parse(f); A.SetFirstSide(q); } if (n.Length != 0) { double w = double.Parse(n); A.SetFirstSide(w); } if (d.Length != 0) { double v = double.Parse(d); A.SetFirstSide(v); } } catch (Exception ex) { MessageBox.Show(ex.Message); } this.Hide(); Changes form = new Changes(A); form.Show(); }