EnvelopeUid Property
Gets UID (Unique-ID) assigned to the message in the folder on the mail server.

Namespace: MailBee.ImapMail
Assembly: MailBee.NET (in MailBee.NET.dll) Version: 11.2.0 build 590 for .NET 4.5
public long Uid { get; }

Property Value

Type: Int64
A positive 32-bit numeric value indicating UID of the message, or -1 if this information is not available.
Unlike ordinal message numbers (MessageNumber property), UIDs persist between operations which re-order messages in a folder (such as deleting and expunging messages). Also, UIDs should persist between different IMAP sessions (some old IMAP4 implementations, however, may violate this rule, see UidValidity topic for details).
See Also