Frequently Asked Questions

                    System.Text.Encoding.RegisterProvider (System.Text.CodePagesEncodingProvider.Instance);
                  

                    System.Text.Encoding.RegisterProvider (System.Text.CodePagesEncodingProvider.Instance);
                  

                    <configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Runtime.CompilerServices.Unsafe" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>
                  

                    // log to a file called 'imap.log'
var client = new ImapClient (new ProtocolLogger ("imap.log"));

// log to standard output (i.e. the console)
var client = new ImapClient (new ProtocolLogger (Console.OpenStandardOutput ()));
                  

                    using (var client = new ImapClient ()) {
    client.Connect ("imap.gmail.com", 993, SecureSocketOptions.SslOnConnect);
    client.Authenticate ("user@gmail.com", "app-specific-password");

    // do stuff...

    client.Disconnect (true);
}
                  

                    const string GMailAccount = "username@gmail.com";

var clientSecrets = new ClientSecrets {
    ClientId = "XXX.apps.googleusercontent.com",
    ClientSecret = "XXX"
};

var codeFlow = new GoogleAuthorizationCodeFlow (new GoogleAuthorizationCodeFlow.Initializer {
    // Cache tokens in ~/.local/share/google-filedatastore/CredentialCacheFolder on Linux/Mac
    DataStore = new FileDataStore ("CredentialCacheFolder", false),
    Scopes = new [] { "https://mail.google.com/" },
    ClientSecrets = clientSecrets
});

var codeReceiver = new LocalServerCodeReceiver ();
var authCode = new AuthorizationCodeInstalledApp (codeFlow, codeReceiver);
var credential = await authCode.AuthorizeAsync (GMailAccount, CancellationToken.None);

if (authCode.ShouldRequestAuthorizationCode (credential.Token))
    await credential.RefreshTokenAsync (CancellationToken.None);

var oauth2 = new SaslMechanismOAuth2 (credential.UserId, credential.Token.AccessToken);

using (var client = new ImapClient ()) {
    await client.ConnectAsync ("imap.gmail.com", 993, SecureSocketOptions.SslOnConnect);
    await client.AuthenticateAsync (oauth2);
    await client.DisconnectAsync (true);
}
                  

                    var message = new MimeMessage ();
message.From.Add (new MailboxAddress ("Joey", "joey@friends.com"));
message.To.Add (new MailboxAddress ("Alice", "alice@wonderland.com"));
message.Subject = "How you doin?";

// create our message text, just like before (except don't set it as the message.Body)
var body = new TextPart ("plain") {
    Text = @"Hey Alice,

What are you up to this weekend? Monica is throwing one of her parties on
Saturday and I was hoping you could make it.

Will you be my +1?

-- Joey
"
};

// create an image attachment for the file located at path
var attachment = new MimePart ("image", "gif") {
    Content = new MimeContent (File.OpenRead (path), ContentEncoding.Unspecified),
    ContentDisposition = new ContentDisposition (ContentDisposition.Attachment),
    ContentTransferEncoding = ContentEncoding.Base64,
    FileName = Path.GetFileName (path)
};

// now create the multipart/mixed container to hold the message text and the
// image attachment
var multipart = new Multipart ("mixed");
multipart.Add (body);
multipart.Add (attachment);

// now set the multipart/mixed as the message body
message.Body = multipart;
                  

                                var message = new MimeMessage ();
            message.From.Add (new MailboxAddress ("Joey", "joey@friends.com"));
            message.To.Add (new MailboxAddress ("Alice", "alice@wonderland.com"));
            message.Subject = "How you doin?";

            var builder = new BodyBuilder ();

            // Set the plain-text version of the message text
            builder.TextBody = @"Hey Alice,

What are you up to this weekend? Monica is throwing one of her parties on
Saturday and I was hoping you could make it.

Will you be my +1?

-- Joey
";

            // We may also want to attach a calendar event for Monica's party...
            builder.Attachments.Add (@"C:\Users\Joey\Documents\party.ics");

            // Now we just need to set the message body and we're done
            message.Body = builder.ToMessageBody ();
                  

                    var attachments = message.BodyParts.OfType<MimePart> ().Where (part => !string.IsNullOrEmpty (part.FileName));
                  

                    /// <summary>
/// Visits a MimeMessage and generates HTML suitable to be rendered by a browser control.
/// </summary>
class HtmlPreviewVisitor : MimeVisitor
{
    List<MultipartRelated> stack = new List<MultipartRelated> ();
    List<MimeEntity> attachments = new List<MimeEntity> ();
    string body;

    /// <summary>
    /// Creates a new HtmlPreviewVisitor.
    /// </summary>
    public HtmlPreviewVisitor ()
    {
    }

    /// <summary>
    /// The list of attachments that were in the MimeMessage.
    /// </summary>
    public IList<MimeEntity> Attachments {
        get { return attachments; }
    }

    /// <summary>
    /// The HTML string that can be set on the BrowserControl.
    /// </summary>
    public string HtmlBody {
        get { return body ?? string.Empty; }
    }

    protected override void VisitMultipartAlternative (MultipartAlternative alternative)
    {
        // walk the multipart/alternative children backwards from greatest level of faithfulness to the least faithful
        for (int i = alternative.Count - 1; i >= 0 && body == null; i--)
            alternative[i].Accept (this);
    }

    protected override void VisitMultipartRelated (MultipartRelated related)
    {
        var root = related.Root;

        // push this multipart/related onto our stack
        stack.Add (related);

        // visit the root document
        root.Accept (this);

        // pop this multipart/related off our stack
        stack.RemoveAt (stack.Count - 1);
    }

    // look up the image based on the img src url within our multipart/related stack
    bool TryGetImage (string url, out MimePart image)
    {
        UriKind kind;
        int index;
        Uri uri;

        if (Uri.IsWellFormedUriString (url, UriKind.Absolute))
            kind = UriKind.Absolute;
        else if (Uri.IsWellFormedUriString (url, UriKind.Relative))
            kind = UriKind.Relative;
        else
            kind = UriKind.RelativeOrAbsolute;

        try {
            uri = new Uri (url, kind);
        } catch {
            image = null;
            return false;
        }

        for (int i = stack.Count - 1; i >= 0; i--) {
            if ((index = stack[i].IndexOf (uri)) == -1)
                continue;

            image = stack[i][index] as MimePart;
            return image != null;
        }

        image = null;

        return false;
    }

    /// <summary>
    /// Get a data: URI for the image attachment.
    /// </summary>
    /// <remarks>
    /// Encodes the image attachment into a string suitable for setting as a src= attribute value in
    /// an img tag.
    /// </remarks>
    /// <returns>The data: URI.</returns>
    /// <param name="image">The image attachment.</param>
    string GetDataUri (MimePart image)
    {
        using (var memory = new MemoryStream ()) {
            image.Content.DecodeTo (memory);
            var buffer = memory.GetBuffer ();
            var length = (int) memory.Length;
            var base64 = Convert.ToBase64String (buffer, 0, length);

            return string.Format ("data:{0};base64,{1}", image.ContentType.MimeType, base64);
        }
    }

    // Replaces <img src=...> urls that refer to images embedded within the message with
    // "file://" urls that the browser control will actually be able to load.
    void HtmlTagCallback (HtmlTagContext ctx, HtmlWriter htmlWriter)
    {
        if (ctx.TagId == HtmlTagId.Meta && !ctx.IsEndTag) {
            bool isContentType = false;

            ctx.WriteTag (htmlWriter, false);

            // replace charsets with "utf-8" since our output will be in utf-8 (and not whatever the original charset was)
            foreach (var attribute in ctx.Attributes) {
                if (attribute.Id == HtmlAttributeId.Charset) {
                    htmlWriter.WriteAttributeName (attribute.Name);
                    htmlWriter.WriteAttributeValue ("utf-8");
                } else if (isContentType && attribute.Id == HtmlAttributeId.Content) {
                    htmlWriter.WriteAttributeName (attribute.Name);
                    htmlWriter.WriteAttributeValue ("text/html; charset=utf-8");
                } else {
                    if (attribute.Id == HtmlAttributeId.HttpEquiv && attribute.Value != null
                        && attribute.Value.Equals ("Content-Type", StringComparison.OrdinalIgnoreCase))
                        isContentType = true;

                    htmlWriter.WriteAttribute (attribute);
                }
            }
        } else if (ctx.TagId == HtmlTagId.Image && !ctx.IsEndTag && stack.Count > 0) {
            ctx.WriteTag (htmlWriter, false);

            // replace the src attribute with a "data:" URL
            foreach (var attribute in ctx.Attributes) {
                if (attribute.Id == HtmlAttributeId.Src) {
                    if (!TryGetImage (attribute.Value, out var image)) {
                        htmlWriter.WriteAttribute (attribute);
                        continue;
                    }

                    var dataUri = GetDataUri (image);

                    htmlWriter.WriteAttributeName (attribute.Name);
                    htmlWriter.WriteAttributeValue (dataUri);
                } else {
                    htmlWriter.WriteAttribute (attribute);
                }
            }
        } else {
            // pass the tag through to the output
            ctx.WriteTag (htmlWriter, true);
        }
    }

    protected override void VisitTextPart (TextPart entity)
    {
        TextConverter converter;

        if (body != null) {
            // since we've already found the body, treat this as an attachment
            attachments.Add (entity);
            return;
        }

        if (entity.IsHtml) {
            converter = new HtmlToHtml {
                HtmlTagCallback = HtmlTagCallback
            };
        } else if (entity.IsFlowed) {
            var flowed = new FlowedToHtml ();
            string delsp;

            if (entity.ContentType.Parameters.TryGetValue ("delsp", out delsp))
                flowed.DeleteSpace = delsp.Equals ("yes", StringComparison.OrdinalIgnoreCase);

            converter = flowed;
        } else {
            converter = new TextToHtml ();
        }

        body = converter.Convert (entity.Text);
    }

    protected override void VisitTnefPart (TnefPart entity)
    {
        // extract any attachments in the MS-TNEF part
        using (var tnef = entity.LoadTnefMessage ()) {
            // the converted message (and its attachments) outlives the TnefMessage
            var result = tnef.ConvertToMime ();

            attachments.AddRange (result.Message.Attachments);
        }
    }

    protected override void VisitMessagePart (MessagePart entity)
    {
        // treat message/rfc822 parts as attachments
        attachments.Add (entity);
    }

    protected override void VisitMimePart (MimePart entity)
    {
        // realistically, if we've gotten this far, then we can treat this as an attachment
        // even if the IsAttachment property is false.
        attachments.Add (entity);
    }
}
                  

                    void Render (MimeMessage message)
{
    var tmpDir = Path.Combine (Path.GetTempPath (), message.MessageId);
    var visitor = new HtmlPreviewVisitor (tmpDir);

    Directory.CreateDirectory (tmpDir);

    message.Accept (visitor);

    DisplayHtml (visitor.HtmlBody);
    DisplayAttachments (visitor.Attachments);
}
                  

                    // Load a MimeMessage from a stream
var message = MimeMessage.Load (stream);
                  

                    // Load a MimeMessage from a file path
var message = MimeMessage.Load ("message.eml");
                  

                    // Load a MimeMessage from a stream
var parser = new MimeParser (stream, MimeFormat.Entity);
var message = parser.ParseMessage ();
                  

                    // Load every message from a Unix mbox
var parser = new MimeParser (stream, MimeFormat.Mbox);
while (!parser.IsEndOfStream) {
    var message = parser.ParseMessage ();

    // do something with the message
}
                  

                    message.WriteTo ("message.eml");
                  

                    // clone the default formatting options
var format = FormatOptions.Default.Clone ();

// override the line-endings to be DOS no matter what platform we are on
format.NewLineFormat = NewLineFormat.Dos;

message.WriteTo (format, "message.eml");
                  

                    using (var stream = File.Create (fileName))
    attachment.Content.DecodeTo (stream);
                  

                    using (var stream = File.Create (fileName))
    attachment.Message.WriteTo (stream);
                  

                    foreach (var attachment in message.Attachments) {
    if (attachment is MessagePart) {
        var fileName = attachment.ContentDisposition?.FileName ?? attachment.ContentType.Name;
        var rfc822 = (MessagePart) attachment;

        if (string.IsNullOrEmpty (fileName))
            fileName = "attached-message.eml";

        // make sure that the filename value does not contain a full path or invalid path characters
        fileName = Path.GetFileName (fileName);

        using (var stream = File.Create (fileName))
            rfc822.Message.WriteTo (stream);
    } else {
        var part = (MimePart) attachment;
        var fileName = part.FileName;

        if (string.IsNullOrEmpty (fileName))
            fileName = "untitled.dat";

        // make sure that the filename value does not contain a full path or invalid path characters
        fileName = Path.GetFileName (fileName);

        using (var stream = File.Create (fileName))
            part.Content.DecodeTo (stream);
    }
}
                  

                    foreach (var mailbox in message.To.Mailboxes)
    Console.WriteLine ("{0}'s email address is {1}", mailbox.Name, mailbox.Address);
                  

                    Parameter param;

if (attachment.ContentDisposition.Parameters.TryGetValue ("filename", out param))
    param.EncodingMethod = ParameterEncodingMethod.Rfc2047;
                  

                    var options = FormatOptions.Default.Clone ();
options.ParameterEncodingMethod = ParameterEncodingMethod.Rfc2047;

message.WriteTo (options, stream);
                  

                    Return-Path: <pgp-enthusiast@example.com>
Received: from [127.0.0.1] (hostname.example.com. [201.95.8.17])
    by mx.google.com with ESMTPSA id l67sm26628445yha.8.2014.04.27.13.49.44
    for <pgp-enthusiast@example.com>
    (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128);
    Sun, 27 Apr 2014 13:49:44 -0700 (PDT)
Message-ID: <535D6D67.8020803@example.com>
Date: Sun, 27 Apr 2014 17:49:43 -0300
From: Die-Hard PGP Fan <pgp-enthusiast@example.com>
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0
MIME-Version: 1.0
To: undisclosed-recipients:;
Subject: Test of inline encrypted PGP blocks
X-Enigmail-Version: 1.6
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-Antivirus: avast! (VPS 140427-1, 27/04/2014), Outbound message
X-Antivirus-Status: Clean

-----BEGIN PGP MESSAGE-----
Charset: ISO-8859-1
Version: GnuPG v2.0.22 (MingW32)
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/

SGFoISBJIGZvb2xlZCB5b3UsIHRoaXMgdGV4dCBpc24ndCBhY3R1YWxseSBlbmNy
eXB0ZWQgd2l0aCBQR1AsCml0J3MgYWN0dWFsbHkgb25seSBiYXNlNjQgZW5jb2Rl
ZCEKCkknbSBqdXN0IHVzaW5nIHRoaXMgYXMgYW4gZXhhbXBsZSwgdGhvdWdoLCBz
byBpdCBkb2Vzbid0IHJlYWxseSBtYXR0ZXIuCgpGb3IgdGhlIHNha2Ugb2YgYXJn
dW1lbnQsIHdlJ2xsIHByZXRlbmQgdGhhdCB0aGlzIGlzIGFjdHVhbGx5IGFuIGVu
Y3J5cHRlZApibHVyYi4gTW1ta2F5PyBUaGFua3MuCg==
-----END PGP MESSAGE-----
                  

                    static Stream Decrypt (MimeMessage message)
{
    var text = message.TextBody;

    using (var encrypted = new MemoryStream (Encoding.ASCII.GetBytes (text), false)) {
        using (var ctx = new MyGnuPGContext ()) {
            var decrypted = new MemoryStream ();

            ctx.DecryptTo (encrypted, decrypted);
            decrypted.Position = 0;

            return decrypted;
        }
    }
}
                  

                    public static MimeMessage Reply (MimeMessage message, MailboxAddress from, bool replyToAll)
{
    var reply = new MimeMessage ();

    reply.From.Add (from);

    // reply to the sender of the message
    if (message.ReplyTo.Count > 0) {
        reply.To.AddRange (message.ReplyTo);
    } else if (message.From.Count > 0) {
        reply.To.AddRange (message.From);
    } else if (message.Sender != null) {
        reply.To.Add (message.Sender);
    }

    if (replyToAll) {
        // include all of the other original recipients (removing ourselves from the list)
        reply.To.AddRange (message.To.Mailboxes.Where (x => x.Address != from.Address));
        reply.Cc.AddRange (message.Cc.Mailboxes.Where (x => x.Address != from.Address));
    }

    // set the reply subject
    if (!message.Subject.StartsWith ("Re:", StringComparison.OrdinalIgnoreCase))
        reply.Subject = "Re: " + message.Subject;
    else
        reply.Subject = message.Subject;

    // construct the In-Reply-To and References headers
    if (!string.IsNullOrEmpty (message.MessageId)) {
        reply.InReplyTo = message.MessageId;
        foreach (var id in message.References)
            reply.References.Add (id);
        reply.References.Add (message.MessageId);
    }

    // quote the original message text
    using (var quoted = new StringWriter ()) {
        var sender = message.Sender ?? message.From.Mailboxes.FirstOrDefault ();
        var name = sender != null ? (!string.IsNullOrEmpty (sender.Name) ? sender.Name : sender.Address) : "someone";

        quoted.WriteLine ("On {0}, {1} wrote:", message.Date.ToString ("f"), name);
        using (var reader = new StringReader (message.TextBody)) {
            string line;

            while ((line = reader.ReadLine ()) != null) {
                quoted.Write ("> ");
                quoted.WriteLine (line);
            }
        }

        reply.Body = new TextPart ("plain") {
            Text = quoted.ToString ()
        };
    }

    return reply;
}
                  

                    public class ReplyVisitor : MimeVisitor
{
    readonly Stack<Multipart> stack = new Stack<Multipart> ();
    MimeMessage message;
    MimeEntity body;

    /// <summary>
    /// Creates a new ReplyVisitor.
    /// </summary>
    public ReplyVisitor ()
    {
    }

    /// <summary>
    /// Gets the reply.
    /// </summary>
    /// <value>The reply.</value>
    public MimeEntity Body {
        get { return body; }
    }

    void Push (MimeEntity entity)
    {
        var multipart = entity as Multipart;

        if (body == null) {
            body = entity;
        } else {
            var parent = stack.Peek ();
            parent.Add (entity);
        }

        if (multipart != null)
            stack.Push (multipart);
    }

    void Pop ()
    {
        stack.Pop ();
    }

    public static string GetOnDateSenderWrote (MimeMessage message)
    {
        var sender = message.Sender != null ? message.Sender : message.From.Mailboxes.FirstOrDefault ();
        var name = sender != null ? (!string.IsNullOrEmpty (sender.Name) ? sender.Name : sender.Address) : "someone";

        return string.Format ("On {0}, {1} wrote:", message.Date.ToString ("f"), name);
    }

    /// <summary>
    /// Visit the specified message.
    /// </summary>
    /// <param name="message">The message.</param>
    public override void Visit (MimeMessage message)
    {
        this.message = message;
        stack.Clear ();

        base.Visit (message);
    }

    protected override void VisitMultipartAlternative (MultipartAlternative alternative)
    {
        var multipart = new MultipartAlternative ();

        Push (multipart);

        for (int i = 0; i < alternative.Count; i++)
            alternative[i].Accept (this);

        Pop ();
    }

    protected override void VisitMultipartRelated (MultipartRelated related)
    {
        var multipart = new MultipartRelated ();
        var root = related.Root;

        Push (multipart);

        root.Accept (this);

        for (int i = 0; i < related.Count; i++) {
            if (related[i] != root)
                related[i].Accept (this);
        }

        Pop ();
    }

    protected override void VisitMultipart (Multipart multipart)
    {
        foreach (var part in multipart) {
            if (part is MultipartAlternative)
                part.Accept (this);
            else if (part is MultipartRelated)
                part.Accept (this);
            else if (part is TextPart)
                part.Accept (this);
        }
    }

    void HtmlTagCallback (HtmlTagContext ctx, HtmlWriter htmlWriter)
    {
        if (ctx.TagId == HtmlTagId.Body && !ctx.IsEmptyElementTag) {
            if (ctx.IsEndTag) {
                // end our opening <blockquote>
                htmlWriter.WriteEndTag (HtmlTagId.BlockQuote);

                // pass the </body> tag through to the output
                ctx.WriteTag (htmlWriter, true);
            } else {
                // pass the <body> tag through to the output
                ctx.WriteTag (htmlWriter, true);

                // prepend the HTML reply with "On {DATE}, {SENDER} wrote:"
                htmlWriter.WriteStartTag (HtmlTagId.P);
                htmlWriter.WriteText (GetOnDateSenderWrote (message));
                htmlWriter.WriteEndTag (HtmlTagId.P);

                // Wrap the original content in a <blockquote>
                htmlWriter.WriteStartTag (HtmlTagId.BlockQuote);
                htmlWriter.WriteAttribute (HtmlAttributeId.Style, "border-left: 1px #ccc solid; margin: 0 0 0 .8ex; padding-left: 1ex;");

                ctx.InvokeCallbackForEndTag = true;
            }
        } else {
            // pass the tag through to the output
            ctx.WriteTag (htmlWriter, true);
        }
    }

    string QuoteText (string text)
    {
        using (var quoted = new StringWriter ()) {
            quoted.WriteLine (GetOnDateSenderWrote (message));

            using (var reader = new StringReader (text)) {
                string line;

                while ((line = reader.ReadLine ()) != null) {
                    quoted.Write ("> ");
                    quoted.WriteLine (line);
                }
            }

            return quoted.ToString ();
        }
    }

    protected override void VisitTextPart (TextPart entity)
    {
        string text;

        if (entity.IsHtml) {
            var converter = new HtmlToHtml {
                HtmlTagCallback = HtmlTagCallback
            };

            text = converter.Convert (entity.Text);
        } else if (entity.IsFlowed) {
            var converter = new FlowedToText ();

            text = converter.Convert (entity.Text);
            text = QuoteText (text);
        } else {
            // quote the original message text
            text = QuoteText (entity.Text);
        }

        var part = new TextPart (entity.ContentType.MediaSubtype.ToLowerInvariant ()) {
            Text = text
        };

        Push (part);
    }

    protected override void VisitMessagePart (MessagePart entity)
    {
        // don't descend into message/rfc822 parts
    }
}
                  

                    public static MimeMessage Reply (MimeMessage message, MailboxAddress from, bool replyToAll)
{
    var visitor = new ReplyVisitor ();
    var reply = new MimeMessage ();

    reply.From.Add (from);

    // reply to the sender of the message
    if (message.ReplyTo.Count > 0) {
        reply.To.AddRange (message.ReplyTo);
    } else if (message.From.Count > 0) {
        reply.To.AddRange (message.From);
    } else if (message.Sender != null) {
        reply.To.Add (message.Sender);
    }

    if (replyToAll) {
        // include all of the other original recipients (removing ourselves from the list)
        reply.To.AddRange (message.To.Mailboxes.Where (x => x.Address != from.Address));
        reply.Cc.AddRange (message.Cc.Mailboxes.Where (x => x.Address != from.Address));
    }

    // set the reply subject
    if (!message.Subject.StartsWith ("Re:", StringComparison.OrdinalIgnoreCase))
        reply.Subject = "Re: " + message.Subject;
    else
        reply.Subject = message.Subject;

    // construct the In-Reply-To and References headers
    if (!string.IsNullOrEmpty (message.MessageId)) {
        reply.InReplyTo = message.MessageId;
        foreach (var id in message.References)
            reply.References.Add (id);
        reply.References.Add (message.MessageId);
    }

    visitor.Visit (message);

    reply.Body = visitor.Body ?? new TextPart ("plain") { Text = ReplyVisitor.GetOnDateSenderWrote (message) + Environment.NewLine };

    return reply;
}
                  

                    public static MimeMessage Forward (MimeMessage original, MailboxAddress from, IEnumerable<InternetAddress> to)
{
    var message = new MimeMessage ();
    message.From.Add (from);
    message.To.AddRange (to);

    // set the forwarded subject
    if (!original.Subject?.StartsWith ("FW:", StringComparison.OrdinalIgnoreCase))
        message.Subject = "FW: " + (original.Subject ?? string.Empty);
    else
        message.Subject = original.Subject;

    // create the main textual body of the message
    var text = new TextPart ("plain") { Text = "Here's the forwarded message:" };

    // create the message/rfc822 attachment for the original message
    var rfc822 = new MessagePart { Message = original };

    // create a multipart/mixed container for the text body and the forwarded message
    var multipart = new Multipart ("mixed");
    multipart.Add (text);
    multipart.Add (rfc822);

    // set the multipart as the body of the message
    message.Body = multipart;

    return message;
}
                  

                    public static MimeMessage Forward (MimeMessage original, MailboxAddress from, IEnumerable<InternetAddress> to)
{
    var message = new MimeMessage ();
    message.From.Add (from);
    message.To.AddRange (to);

    // set the forwarded subject
    if (!original.Subject?.StartsWith ("FW:", StringComparison.OrdinalIgnoreCase))
        message.Subject = "FW: " + (original.Subject ?? string.Empty);
    else
        message.Subject = original.Subject;

    // quote the original message text
    using (var text = new StringWriter ()) {
        text.WriteLine ();
        text.WriteLine ("-----Original Message-----");
        test.WriteLine ("From: {0}", original.From);
        text.WriteLine ("Sent: {0}", DateUtils.FormatDate (original.Date));
        text.WriteLine ("To: {0}", original.To);
        text.WriteLine ("Subject: {0}", original.Subject ?? string.Empty);
        text.WriteLine ();

        text.Write (original.TextBody);

        message.Body = new TextPart ("plain") {
            Text = text.ToString ()
        };
    }

    return message;
}
                  

                    MimeEntity ParseMultipartFormData (HttpWebResponse response)
{
    var contentType = ContentType.Parse (response.ContentType);

    return MimeEntity.Load (contentType, response.GetResponseStream ());
}
                  

                    MimeEntity ParseMultipartFormData (HttpWebResponse response, Stream stream)
{
    // The caller supplies an empty, readable, writable, seekable temporary-file stream
    // and keeps it open and unchanged until the returned entity is no longer needed.

    // create a header for the multipart/form-data MIME entity based on the Content-Type value of the HTTP
    // response
    var header = Encoding.UTF8.GetBytes (string.Format ("Content-Type: {0}\r\n\r\n", response.ContentType));

    // write the header to the stream
    stream.Write (header, 0, header.Length);

    // copy the content of the HTTP response to our temporary stream
    response.GetResponseStream ().CopyTo (stream);

    // reset the stream back to the beginning
    stream.Position = 0;

    // reference the source stream instead of loading the content into memory
    return MimeEntity.Load (stream, storage: MimeContentStorage.Source);
}
                  

                    folder.Status (StatusItems.Count | StatusItems.Unread);

int total = folder.Count;
int unread = folder.Unread;
                  

                    foreach (var uid in folder.Search (SearchQuery.NotSeen)) {
    var message = folder.GetMessage (uid);
}
                  

                    var query = SearchQuery.DeliveredAfter (dateRange.BeginDate)
    .And (SearchQuery.DeliveredBefore (dateRange.EndDate));
var results = folder.Search (query);
                  

                    var query = SearchQuery.Not (SearchQuery.DeliveredBefore (dateRange.BeginDate)
    .Or (SearchQuery.DeliveredAfter (dateRange.EndDate)));
var results = folder.Search (query);
                  

                    lock (client.SyncRoot) {
    client.NoOp ();
}
                  

                    folder.AddFlags (uids, MessageFlags.Seen, true);
                  

                    folder.RemoveFlags (uids, MessageFlags.Seen, true);
                  

                    /// <summary>
/// Just a simple class to represent the cached information about a message.
/// </summary>
class CachedMessageInfo
{
    public UniqueId UniqueId;
    public MessageFlags Flags;
    public IEnumerable<string> Keywords;
    public Envelope Envelope;
    public BodyPart Body;
}

/// <summary>
/// Resynchronize the cache with the remote IMAP folder.
/// </summary>
/// <param name="folder">The IMAP folder.</param>
/// <param name="cache">The local cache of message metadata.</param>
/// <param name="cachedUidValidity">The cached UIDVALIDITY value of the IMAP folder from a previous session.</param>
static void ResyncFolder (ImapFolder folder, List<CachedMessageInfo> cache, ref uint cachedUidValidity)
{
    IList<IMessageSummary> summaries;

    // Step 1: Open the folder.

    // Note: we only need read-only access to update our cache, but depending on
    // what you plan to do with the folder after resynchronizing, you may want
    // to open the folder in read-write mode instead.
    folder.Open (FolderAccess.ReadOnly);

    if (cache.Count > 0) {
        if (folder.UidValidity == cachedUidValidity) {
            // Step 2: Remove messages from our cache that no longer exist on the server.

            // get the full list of UIDs on the server...
            var all = folder.Search (SearchQuery.All);

            // remove any messages from our cache that no longer exist...
            for (int i = 0; i < cache.Count; i++) {
                if (!all.Contains (cache[i].UniqueId)) {
                    cache.RemoveAt (i);
                    i--;
                }
            }

            // Step 3: Sync any flag changes for our cached messages.

            // get a list of known uids... astute observers will note that an easy
            // optimization to make here would be to merge this loop with the above
            // loop.
            var known = new UniqueIdSet (SortOrder.Ascending);
            for (int i = 0; i < cache.Count; i++)
                known.Add (cache[i].UniqueId);

            // fetch the flags for our known messages...
            summaries = folder.Fetch (known, MessageSummaryItems.Flags);
            for (int i = 0; i < summaries.Count; i++) {
                // Note: the indexes should match up with our cache, but it wouldn't
                // hurt to add error checking to make sure. I'm not bothering to here
                // for simplicity reasons.
                cache[i].Flags = summaries[i].Flags.Value;
                cache[i].Keywords = summaries[i].Keywords;
            }
        } else {
            // The UIDVALIDITY of the folder has changed. This means that our entire
            // cache is obsolete. We need to clear our cache and start from scratch.
            cachedUidValidity = folder.UidValidity;
            cache.Clear ();
        }
    } else {
        // We have nothing cached, so just start from scratch.
        cachedUidValidity = folder.UidValidity;
    }

    // Step 4: Fetch the messages we don't already know about and add them to our cache.

    summaries = folder.Fetch (cache.Count, -1, MessageSummaryItems.UniqueId | MessageSummaryItems.Flags | MessageSummaryItems.Envelope | MessageSummaryItems.BodyStructure);
    for (int i = 0; i < summaries.Count; i++) {
        cache.Add (new CachedMessageInfo {
            UniqueId = summaries[i].UniqueId,
            Flags = summaries[i].Flags.Value,
            Keywords = summaries[i].Keywords,
            Envelope = summaries[i].Envelope,
            Body = summaries[i].Body
        });
    }

    // Tada! Now we are resynchronized with the server!
}
                  

                    var result = await GetPublicClientOAuth2CredentialsAsync ("IMAP", "sharedMailboxName@custom-domain.com");

// Note: We always use result.Account.Username instead of `Username` because the user may have selected an alternative account.
var oauth2 = new SaslMechanismOAuth2 (result.Account.Username, result.AccessToken);

using (var client = new ImapClient ()) {
    await client.ConnectAsync ("outlook.office365.com", 993, SecureSocketOptions.SslOnConnect);
    await client.AuthenticateAsync (oauth2);

    // ...

    await client.DisconnectAsync (true);
}
                  

                    using (var mbox = File.Open ("C:\\path\\to\\Sent Mail.mbox", FileMode.Append, FileAccess.Write)) {
    var marker = string.Format ("From MAILER-DAEMON {0}{1}", DateTime.Now.ToString ("ddd MMM d HH:mm:ss yyyy", CultureInfo.InvariantCulture), Environment.NewLine);
    var bytes = Encoding.ASCII.GetBytes (marker);

    // Write the mbox marker bytes.
    mbox.Write (bytes, 0, bytes.Length);

    // Write the message, making sure to escape any line that looks like an mbox From-marker.
    using (var filtered = new FilteredStream (mbox)) {
        filtered.Add (new MboxFromFilter ());
        message.WriteTo (filtered);
        filtered.Flush ();
    }

    mbox.Flush ();
}
                  

                    using (var client = new ImapClient ()) {
    client.Connect ("imap.server.com", 993, SecureSocketOptions.SslOnConnect);
    client.Authenticate ("username", "password");

    IMailFolder sentMail;

    if (client.Capabilities.Contains (ImapCapability.SpecialUse)) {
        sentMail = client.GetFolder (SpecialFolder.Sent);
    } else {
        var personal = client.GetFolder (client.PersonalNamespaces[0]);

        // Note: This assumes that the "Sent Mail" folder lives at the root of the folder hierarchy
        // and is named "Sent Mail" as opposed to "Sent" or "Sent Items" or any other variation.
        sentMail = personal.GetSubfolder ("Sent Mail");
    }

    sentMail.Append (message, MessageFlags.Seen);

    client.Disconnect (true);
}
                  

                    public static void SaveToPickupDirectory (MimeMessage message, string pickupDirectory)
{
    do {
        // Generate a random file name to save the message to.
        var path = Path.Combine (pickupDirectory, Guid.NewGuid ().ToString () + ".eml");
        Stream stream;

        try {
            // Attempt to create the new file.
            stream = File.Open (path, FileMode.CreateNew);
        } catch (IOException) {
            // If the file already exists, try again with a new Guid.
            if (File.Exists (path))
                continue;

            // Otherwise, fail immediately since it probably means that there is
            // no graceful way to recover from this error.
            throw;
        }

        try {
            using (stream) {
                // IIS pickup directories expect the message to be "byte-stuffed"
                // which means that lines beginning with "." need to be escaped
                // by adding an extra "." to the beginning of the line.
                //
                // Use an SmtpDataFilter "byte-stuff" the message as it is written
                // to the file stream. This is the same process that an SmtpClient
                // would use when sending the message in a `DATA` command.
                using (var filtered = new FilteredStream (stream)) {
                    filtered.Add (new SmtpDataFilter ());

                    // Make sure to write the message in DOS (CRLF) format.
                    var options = FormatOptions.Default.Clone ();
                    options.NewLineFormat = NewLineFormat.Dos;

                    message.WriteTo (options, filtered);
                    filtered.Flush ();
                    return;
                }
            }
        } catch {
            // An exception here probably means that the disk is full.
            //
            // Delete the file that was created above so that incomplete files are not
            // left behind for IIS to send accidentally.
            File.Delete (path);
            throw;
        }
    } while (true);
}
                  

                    // Add the following header to tell the recipient's client that you want to receive a
// notification when the message has been read by the user.
message.Headers[HeaderId.DispositionNotificationTo] = new MailboxAddress ("My Name", "me@example.com").ToString (true);
                  

                    var report = message.Body as MultipartReport;
if (report != null && report.ReportType.Equals ("disposition-notification", StringComparison.OrdinalIgnoreCase)) {
    // This is a read receipt notification.
}
                  

                    var notification = report[1] as MessageDispositionNotification;
if (notification != null) {
    // Get the Message-Id of the message this notification is for...
    var messageId = notification.Fields["Original-Message-Id"];
}