將附件從電子郵件直接下載到FTP服務器

Question

我開發的方法可以成功地將電子郵件附件下載到本地PC。
我也必須直接從郵件下載到ftp服務器。
我試圖實現我認爲應該工作的功能。
當我成功獲得FileAttachment對象時，我嘗試使用其屬性ContentLocation來獲取附件URL
然後我將該URL傳遞給webClient.DownloadString（）方法。
但不幸的是，屬性ContentLocation始終爲空。
所以我在這行代碼中有一個異常。
這裏是我的意見的方式完整列表：

var service = new ExchangeService(ExchangeVersion.Exchange2013); 
    service.Credentials = new NetworkCredential(serviceUserName, servicePassword); 

    service.Url = new Uri(serviceUrl); 
    ServicePointManager.ServerCertificateValidationCallback = delegate { return true; }; 
    var path = System.IO.Directory.CreateDirectory(Path.Combine(applicationPath, name)); 

    //Filters 
    List<SearchFilter> searchANDFilterCollection = new List<SearchFilter>(); 
    searchANDFilterCollection.Add(new SearchFilter.IsEqualTo(EmailMessageSchema.IsRead, false)); 
    searchANDFilterCollection.Add(new SearchFilter.IsEqualTo(EmailMessageSchema.From, new EmailAddress(email))); 
    SearchFilter sf = 
     new SearchFilter.SearchFilterCollection(LogicalOperator.And, searchANDFilterCollection.ToArray()); 
    FindItemsResults<Item> findResults; 
    ItemView view = new ItemView(10); 
    do 
    { 
     findResults = service.FindItems(WellKnownFolderName.Inbox, sf, view); 
     if (findResults != null && findResults.Items != null && findResults.Items.Count > 0) 
      foreach (EmailMessage item in findResults) 
      { 
       var message = EmailMessage.Bind(service, item.Id, new PropertySet(BasePropertySet.IdOnly, ItemSchema.Attachments, ItemSchema.HasAttachments)); 
       foreach (Attachment attachment in message.Attachments) 
       { 
        if (attachment is FileAttachment) 
        { 
         if (attachment.Name.Contains(".xlsx") || attachment.Name.Contains(".xlsb") || attachment.Name.Contains(".xls") || attachment.Name.Contains(".csv")) 
         { 
          var fileAttachment = attachment as FileAttachment; 

          //Download to ftp 
          if (isSaveToFTP) 
          { 
           var webClient = new WebClient(); 
           string readHtml = webClient.DownloadString(fileAttachment.ContentLocation); 
           byte[] buffer = Encoding.Default.GetBytes(readHtml); 

           WebRequest makeDirectory = WebRequest.Create(Path.Combine(ftpAddress, name)); 
           makeDirectory.Method = WebRequestMethods.Ftp.MakeDirectory; 
           makeDirectory.Credentials = new NetworkCredential(username, password); 
           WebRequest uploadFile = WebRequest.Create(ftpAddress + name + "/" + fileAttachment.Name); 
           uploadFile.Method = WebRequestMethods.Ftp.UploadFile; 
           uploadFile.Credentials = new NetworkCredential(username, password); 
           Stream reqStream = uploadFile.GetRequestStream(); 
           reqStream.Write(buffer, 0, buffer.Length); 
           reqStream.Close(); 
          } 
          //Download to pc 
          else fileAttachment.Load(String.Format(@"{0}\{1}", path, fileAttachment.Name)); 
         } 
        } 
        //fileAttachment.Load(path.Name); 
       } 
      } 


     // mark email as read 
     item.IsRead = true; 
     item.Update(ConflictResolutionMode.AlwaysOverwrite); 
     } 
    } 
    while (findResults.MoreAvailable); 

我應該改變，以得到這個工作？
或者還有其他解決方案嗎？

Answer 1

我認爲ContentLocation依賴於消息創建者。我認爲你想要做的是使用Load(Stream)將內容拖入Stream中，然後根據isSaveToFTP標誌選擇寫入Stream的位置。

Answer 2

這是基於richrdsonmarkj的答案的解決方案：

if (isSaveToFTP) 
     { 
      using (WebClient webClient = new WebClient()) 
      { 
       Stream stream = new MemoryStream(); 
       fileAttachment.Load(stream); 
       using (var reader = new StreamReader(stream)) 
       { 
        byte[] buffer = Encoding.Default.GetBytes(reader.ReadToEnd()); 
        WebRequest uploadFile = WebRequest.Create(ftpAddress + name + "/" + fileAttachment.Name); 
        uploadFile.Method = WebRequestMethods.Ftp.UploadFile; 
        uploadFile.Credentials = new NetworkCredential(username, password); 
        Stream reqStream = uploadFile.GetRequestStream(); 
        reqStream.Write(buffer, 0, buffer.Length); 
        reqStream.Close(); 
       } 
      }