private void SignUpButton_Click(object sender, EventArgs e) { string errors = ""; if (string.IsNullOrWhiteSpace(NameTextBox.Text)) { errors += "Name is empty.\n"; } if (string.IsNullOrEmpty(FirstEventComboBox.Text)) { errors += "Please choose the first event.\n"; } if (string.IsNullOrEmpty(SecondEventComboBox.Text)) { errors += "Please choose the second event.\n"; } if (errors != "") { MessageBox.Show(errors, "Notification", MessageBoxButtons.OK, MessageBoxIcon.Warning); return; } try { Enum.TryParse(FirstEventComboBox.Text, out Event event1); Enum.TryParse(SecondEventComboBox.Text, out Event event2); Controller.AddParticipant(NameTextBox.Text, Convert.ToInt32(AgeSpinner.Value), event1, event2); MessageBox.Show("Registration complete", "Notification", MessageBoxButtons.OK, MessageBoxIcon.Information); } catch (Exception ex) { MessageBox.Show(ex.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } }