IMail To, Cc, Bcc and ReplyTo properties are of IList type.
The reason for this, is to handle not only regular mailboxes but also email groups:
public class MailBox : MailAddress
public class MailGroup : MailAddress
The simplest way to access actual email addresses is to use overloaded
GetMailboxes method:
IMail mail = ...;
foreach (MailAddress address in mail.To)
{
foreach (MailBox mailbox in address.GetMailboxes())
{
Console.WriteLine("{0} <{1}>", mailbox.Name, mailbox.Address);
}
}
You can find more info here:
https://www.limilabs.com/blog/how-to-access-to-cc-bcc-fields