序列化 FileStream 以进行传输

Posted 2023-03-15

【中文标题】序列化 FileStream 以进行传输

【英文标题】：Serialize a FileStream for transport

【发布时间】：2010-10-01 18:57:59

【问题描述】：

另请参阅此问题：Can I pass a System.Net.MailMessage to a WCF service?

我想在发送的邮件中添加附件。附件可以是本地磁盘上的文件，也可以是动态创建的流。 WCF 协定可以包含 Stream，但仅当所有参数都是 Stream 类型时。那么，将一个或多个附件传递给 WCF 服务的最佳方式是什么？

【参考方案1】：

好的，我自己解决了这个问题。这里的技巧是将附件转换为 Base64 编码字符串，与电子邮件系统执行此操作的方式非常相似。我创建了一个类来处理这个问题。在这里发布给其他人：

 [DataContract]
    public class EncodedAttachment
    
        [DataMember(IsRequired=true)]
        public string Base64Attachment;

        [DataMember(IsRequired = true)]
        public string Name;

        /// <summary>
        /// One of the System.Net.Mime.MediaTypeNames
        /// </summary>
        [DataMember(IsRequired = true)]
        public string MediaType;
    

 public EncodedAttachment CreateAttachment(string fileName)
        
            EncodedAttachment att = new EncodedAttachment();
            if (!File.Exists(fileName))
                throw new FileNotFoundException("Cannot create attachment because the file was not found", fileName);

            FileInfo fi = new FileInfo(fileName);
            att.Name = fi.Name;
            att.MediaType = System.Net.Mime.MediaTypeNames.Text.Plain;

            using (FileStream reader = new FileStream(fileName, FileMode.Open))
            
                byte[] buffer = new byte[reader.Length];
                reader.Read(buffer, 0, (int)reader.Length);
                att.Base64Attachment = Convert.ToBase64String(buffer);
            
            return att;
        

在客户端：

public void SendEmail(SmallMessage msg)
        
            using (MailMessage message = new MailMessage())
            
                message.Body = msg.Body;
                message.Subject = msg.Subject;
                message.To.Add(new MailAddress(msg.To));
                message.From = new MailAddress(msg.From);
                foreach (EncodedAttachment att in msg.Attachments)
                
                    message.Attachments.Add(CreateAttachment(att));
                

                SmtpClient client = new SmtpClient();
                client.Send(message);
            
        


Attachment CreateAttachment(EncodedAttachment encodedAtt)

    MemoryStream reader = new MemoryStream(Convert.FromBase64String(encodedAtt.Base64Attachment));
    Attachment att = new Attachment(reader, encodedAtt.Name, encodedAtt.MediaType);
    return att;