private void ValidateUnicodeRequirement(MailMessage message, MailAddressCollection recipients, bool allowUnicode)
{
// Check all recipients, to, from, sender, bcc, cc, etc...
// GetSmtpAddress will throw if !allowUnicode and the username contains non-ascii
foreach (MailAddress address in recipients)
{
address.GetSmtpAddress(allowUnicode);
}
if (message.Sender != null)
{
message.Sender.GetSmtpAddress(allowUnicode);
}
message.From.GetSmtpAddress(allowUnicode);
}