private void nextSubnetButt_Click(object sender, System.EventArgs e) { if (ip == null || ip.getIp() == null || fill) { return; } nextNumOfHosts.BackColor = Color.White; try { int hosts = Int32.Parse(nextNumOfHosts.Text); IPTool newIp = ip.getNextSubNet(hosts); if (newIp == null) { //ToManyHosts noticeLabel.Text = "Info stuff: Number of hosts in this network-class not possible!"; return; } ip = newIp; ipAddress.Text = ip.getIp(); } catch (System.FormatException) { nextNumOfHosts.BackColor = Color.Red; return; } catch (Exception e1) { MessageBox.Show(e1.StackTrace); return; } fillIPCalc(); }