如何在 C# 中使用 EWS API 2.0 从电子邮件线程下载所有附件

Question

我已成功设置并从 EWS 下载附件，这是我正在处理的简短代码：

 EmailMessage message = EmailMessage.Bind(service, item.Id, new PropertySet(BasePropertySet.IdOnly, ItemSchema.Attachments, ItemSchema.HasAttachments));

                           foreach (Attachment attachment in message.Attachments)
                           {
                               if (attachment is FileAttachment)
                               {
                                   string sFilePath;
                                   FileAttachment fileAttachment = attachment as FileAttachment;

我遇到了一个问题，它只从最新的电子邮件线程而不是以前的线程下载附件。看看下面的电子邮件场景，我向我的朋友发送了一封带有附件 1 的电子邮件，他用附件 2 回复了我。我如何从电子邮件中检索附件并与它们所属的电子邮件线程相关联。

电子邮件场景：

This is Second thread with new attachment

Attachment 2

On Tue, Sep 1, 2015 at 9:53 PM, stash it > wrote:

Checking Document Attachment

Attachment 1

Answer 1

我想通了：

ConversationId convId = item.ConversationId; 

PropertySet properties = new PropertySet(BasePropertySet.IdOnly,                                                       
                                                ItemSchema.Subject,
                                                ItemSchema.InReplyTo,
                                                ItemSchema.DateTimeReceived,
                                                ItemSchema.DateTimeSent,
                                                ItemSchema.DisplayCc,
                                                ItemSchema.IsFromMe,                                                         
                                                ItemSchema.DisplayTo,
                                                ItemSchema.HasAttachments,
                                                ItemSchema.Attachments,
                                                ItemSchema.UniqueBody);

// Request conversation items. This results in a call to the service.         
ConversationResponse response = service.GetConversationItems
(convId,properties,null,null,
ConversationSortOrder.TreeOrderDescending);

foreach (ConversationNode node in response.ConversationNodes)
{
    foreach (Item item in node.Items)                   
         {
        Console.WriteLine("   Received: " + item.DateTimeReceived);
        Console.WriteLine("   Received: " + item.uniquebody);
        Console.WriteLine("   Received: " + item.subject);
         if (item.HasAttachments)
                 {
              foreach(Attachment attach in item.Attachments)
                           {
                FileAttachment fileAttachment = attach as FileAttachment;
                fileAttachment.Load(sFilePath);
                }
          }
      }
}

参考： https://msdn.microsoft.com/en-us/library/office/dn610351(v=exchg.150).aspx