如何使用 OpenPop 保存电子邮件附件

Question

我创建了一个网络电子邮件应用程序，我如何查看和保存附件？

我使用的是OpenPop，第三方dll，可以发送带附件的邮件，也可以阅读不带附件的邮件。

这很好用：

Pop3Client pop3Client = (Pop3Client)Session["Pop3Client"]; // Creating newPopClient 
int messageNumber = int.Parse(Request.QueryString["MessageNumber"]);
Message message = pop3Client.GetMessage(messageNumber);
MessagePart messagePart = message.MessagePart.MessageParts[1];
lblFrom.Text = message.Headers.From.Address; // Writeing message. 
lblSubject.Text = message.Headers.Subject;
lblBody.Text=messagePart.BodyEncoding.GetString(messagePart.Body);

第二部分代码显示附件的内容，但只有在它是文本文件时才有用。我需要能够保存附件。此外，我在此处的代码的底部部分会覆盖我的邮件正文，因此如果我收到附件，我将无法查看我的邮件正文。

if (messagePart.IsAttachment == true) { 
    foreach (MessagePart attachment in message.FindAllAttachments()) { 
        if (attachment.FileName.Equals("blabla.pdf")) { // Save the raw bytes to a file
            File.WriteAllBytes(attachment.FileName, attachment.Body); //overwrites MessagePart.Body with attachment 
        } 
    } 
}

Answer 1

    private KeyValuePair<byte[], FileInfo> parse(MessagePart part)
    {
        var _steam = new MemoryStream();
        part.Save(_steam);
        //...
        var _info = new FileInfo(part.FileName);
        return new KeyValuePair<byte[], FileInfo>(_steam.ToArray(), _info);
    }

    //... How to use
    var _attachments = message 
        .FindAllAttachments()
        .Select(a => parse(a))
    ;

Answer 2

如果有人仍在寻找答案，这对我来说很好。

var client = new Pop3Client();
try
{            
    client.Connect("MailServerName", Port_Number, UseSSL); //UseSSL true or false
    client.Authenticate("UserID", "password");   

    var messageCount = client.GetMessageCount();
    var Messages = new List<Message>(messageCount);

    for (int i = 0;i < messageCount; i++)
    {
        Message getMessage = client.GetMessage(i + 1);
        Messages.Add(getMessage);
    }

    foreach (Message msg in Messages)
    {
        foreach (var attachment in msg.FindAllAttachments())
        {
            string filePath = Path.Combine(@"C:\Attachment", attachment.FileName);
            if(attachment.FileName.Equals("blabla.pdf"))
            {
                FileStream Stream = new FileStream(filePath, FileMode.Create);
                BinaryWriter BinaryStream = new BinaryWriter(Stream);
                BinaryStream.Write(attachment.Body);
                BinaryStream.Close();
            }
        }
    }
}
catch (Exception ex)
{
    Console.WriteLine("", ex.Message);
}
finally
{
    if (client.Connected)
        client.Dispose();
}

Answer 3

 List<Message> lstMessages = FetchAllMessages("pop.mail-server.com", 995, true,"Your Email ID", "Your Password");

上面的代码行使用相应的弹出邮件服务器从您的电子邮件中获取所有消息的列表。

例如，要获取列表中最新（或第一封）电子邮件的附件，您可以编写以下代码。

 List<MessagePart> lstAttachments = lstMessages[0].FindAllAttachments();  //Gets all the attachments associated with latest (or first) email from the list.
 for (int attachment = 0; attachment < lstAttachments.Count; attachment++)
 {
         FileInfo file = new FileInfo("Some File Name");
         lstAttachments[attachment].Save(file);
 } 

Answer 4

以防万一有人想要 VB.NET 的代码：

For Each emailAttachment In client.GetMessage(count).FindAllAttachments
    AttachmentName = emailAttachment.FileName
    '----// Write the file to the folder in the following format: <UniqueID> followed by two underscores followed by the <AttachmentName>
    Dim strmFile As New FileStream(Path.Combine("C:\Test\Attachments", EmailUniqueID & "__" & AttachmentName), FileMode.Create)
    Dim BinaryStream = New BinaryWriter(strmFile)
    BinaryStream.Write(emailAttachment.Body)
    BinaryStream.Close()
Next

Answer 5

对于未来的读者来说，更新版本的 Pop3 有更简单的方法

using( OpenPop.Pop3.Pop3Client client = new Pop3Client())
        {
            client.Connect("in.mail.Your.Mailserver.com", 110, false);
            client.Authenticate("usernamePop3", "passwordPop3", AuthenticationMethod.UsernameAndPassword);
            if (client.Connected)
            {
                int messageCount = client.GetMessageCount();
                List<Message> allMessages = new List<Message>(messageCount);
                for (int i = messageCount; i > 0; i--)
                {
                    allMessages.Add(client.GetMessage(i));
                }
                foreach (Message msg in allMessages)
                {
                    var att = msg.FindAllAttachments();
                    foreach (var ado in att)
                    {
                        ado.Save(new System.IO.FileInfo(System.IO.Path.Combine("c:\\xlsx", ado.FileName)));
                    }
                }
            }
           }

Answer 6

这是我很久以前写的，但请看一下我用来在 POP 服务器上的电子邮件消息中保存 XML 附件的这段代码：

OpenPOP.POP3.POPClient client = new POPClient("pop.yourserver.co.uk", 110, "your@email.co.uk", "password_goes_here", AuthenticationMethod.USERPASS); 
if (client.Connected) {
int msgCount = client.GetMessageCount();

/* Cycle through messages */
for (int x = 0; x < msgCount; x++)
    {
        OpenPOP.MIMEParser.Message msg = client.GetMessage(x, false);
        if (msg != null) {
            for (int y = 0; y < msg.AttachmentCount; y++)
            {
                Attachment attachment = (Attachment)msg.Attachments[y];

                if (string.Compare(attachment.ContentType, "text/xml") == 0)
                {
                    System.Xml.XmlDocument doc = new System.Xml.XmlDocument();

                    string xml = attachment.DecodeAsText();
                    doc.LoadXml(xml);
                    doc.Save(@"C:\POP3Temp\test.xml");
                }
            }
        }
    }
}

Answer 7

OpenPop.Mime.Message 类具有 ToMailMessage() 方法，可将 OpenPop 的 Message 转换为 System.Net.Mail.MailMessage，该 System.Net.Mail.MailMessage 具有 Attachments 属性。尝试从那里提取附件。