public void ExistingDonor(decimal donationAmount, int donorId) { string messageBoxText = "Thank you {0} for your donation of £{1:#.00}!{2}Your highest donor tier is {3}!"; Donor donor = SarreWindmillTrust.ExistingDonor(donationAmount, uiDonationDateTimePicker.Value, donorId); MessageBox.Show(String.Format(messageBoxText, donor.Name, donationAmount, Environment.NewLine, SarreWindmillTrust.DonorTier(donor))); }