Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
410 views
in Technique[技术] by (71.8m points)

c# - Saving attachments using MailKit library ?

I'm trying to learn how to use the MailKit library but I am struggling to retrieve attachments. So far my code will open a mailbox, go through each message and store data such as sender, subject, body, date etc. but I can't deal with attachments.

I have tried to use other peoples solutions found on here, on github and other sites but I still don't understand exactly what they are doing in their code and when I come close to getting a solution working it causes more bugs so I get stressed and delete all the code. I don't mean to seem lazy but I would love if somebody could explain how I can achieve this. I'm basically trying to build a mail client for a web forms app.

Below is my code, so as you can see I'm fairly clueless :)

        // Open the Inbox folder
        client.Inbox.Open(FolderAccess.ReadOnly, cancel.Token);

        //get the full summary information to retrieve all details
        var summary = client.Inbox.Fetch(0, -1, MessageSummaryItems.Full, cancel.Token);
        foreach (var msg in summary)
        {
            //this code originally downloaded just the text from the body
            var text = msg.Body as BodyPartText;
            //but I tried altering it so that it will get attachments here also
            var attachments = msg.Body as BodyPartBasic;

            if (text == null)
            {
                var multipart = msg.Body as BodyPartMultipart;

                if (multipart != null)
                {
                    text = multipart.BodyParts.OfType<BodyPartText>().FirstOrDefault();
                }
            }

            if (text == null)
                continue;

            //I hoped this would get the messages where the content dispositon was not null
            //and let me do something like save the attachments somewhere but instead it throws exceptions
            //about the object reference not set to an instance of the object so it's very wrong
            if (attachments.ContentDisposition != null && attachments.ContentDisposition.IsAttachment)
            {
                //I tried to do the same as I did with the text here and grab the body part....... but no 
                var attachedpart = client.Inbox.GetBodyPart(msg.Index, attachments, cancel.Token);
            }

            else 
            {
                //there is no plan b :(
            }

            // this will download *just* the text 
            var part = client.Inbox.GetBodyPart(msg.Index, text, cancel.Token);
            //cast main body text to Text Part
            TextPart _body = (TextPart)part;
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

I'm not entirely clear on what you want to accomplish, but if you just want to download the message attachments (without downloading the entire message) and save those attachments to the file system, here's how you can accomplish that:

var messages = client.Inbox.Fetch (0, -1, MessageSummaryItems.Full | MessageSummaryItems.UniqueId);
int unnamed = 0;

foreach (var message in messages) {
    var multipart = message.Body as BodyPartMultipart;
    var basic = message.Body as BodyPartBasic;

    if (multipart != null) {
        foreach (var attachment in multipart.BodyParts.OfType<BodyPartBasic> ().Where (x => x.IsAttachment)) {
            var mime = (MimePart) client.Inbox.GetBodyPart (message.UniqueId.Value, attachment);
            var fileName = mime.FileName;

            if (string.IsNullOrEmpty (fileName))
                fileName = string.Format ("unnamed-{0}", ++unnamed);

            using (var stream = File.Create (fileName))
                mime.ContentObject.DecodeTo (stream);
        }
    } else if (basic != null && basic.IsAttachment) {
        var mime = (MimePart) client.Inbox.GetBodyPart (message.UniqueId.Value, basic);
        var fileName = mime.FileName;

        if (string.IsNullOrEmpty (fileName))
            fileName = string.Format ("unnamed-{0}", ++unnamed);

        using (var stream = File.Create (fileName))
            mime.ContentObject.DecodeTo (stream);
    }
}

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

1.4m articles

1.4m replys

5 comments

57.0k users

...