ExchangeService怎么设置文件流形式的附件

ExchangeService在Microsoft Exchange Web Services (EWS) 中用于访问Exchange邮箱服务器的数据。如果你想通过ExchangeService发送或接收以文件流形式的附件，你可以按照以下步骤操作：

1. **获取ExchangeService实例**: 首先，你需要创建一个`ExchangeService`对象，通常会配置为使用Exchange Online或On-Premises服务器。

ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2016);
service.Credentials = new WebCredentials("username", "password");
service.Url = new Uri("https://outlook.office365.com/EWS/Exchange.asmx");

2. **构建Attachment对象**: 创建一个`ItemAttachment`或`FileAttachment`对象，取决于你的附件是从本地还是从网络路径来的。

   Attachment attachment;
   if (attachmentStream.IsStream)
   {
       FileAttachment fileAttach = new FileAttachment(attachmentStream, "filename.ext");
       // 或者如果是内存中的二进制数据，使用ItemAttachment
       ItemAttachment itemAttach = new ItemAttachment(new byte[] { /* binary data here */ }, "filename.ext");
       attachment = fileAttach; // 或者itemAttach;
   }
   else
   {
       throw new ArgumentException("attachmentStream should be a Stream or a valid file path.");
   }

3. **添加附件到邮件**: 在构造邮件请求时，将附件添加到`Items`集合。

Message msg = new Message();
msg.Subject = "Subject";
msg.Body = new ItemBody("Plain text body");

// 添加附件到邮件
msg.Attachments.Add(attachment);

SaveChangesRequest request = new SaveChangesRequest(service);
request.Messages.AddRange(msg);

4. **发送请求**: 使用`service.Send(request)`方法发送包含文件流附件的邮件。