开发Outlook加载项以上载附件

Question

我想开发Office Outlook插件，以便在电子邮件附件超过20 MB到OneDrive或SharePoint Online时上传电子邮件附件，并在发送时为邮件正文添加附件链接。

我需要一些指南才能开始，只要告诉我方向，我就会走它。

更新： 我已经开发了一部分，但是一旦代码到达 clientContext.ExecuteQuery（）; outlook崩溃。

private void ApplicationOnItemSend(object item, ref bool cancel)
{
    var mailItem = item as Outlook.MailItem;

    //Upload to SharePoint
    foreach (Outlook.Attachment attachment in mailItem.Attachments)
    {
        if (IsAttachmentExceedLimit(attachment))
        {
            byte[] attachmentData = null;

            // this is a standard attached object
            attachmentData = attachment.PropertyAccessor.GetProperty(PrAttachDataBin) as byte[];

            MemoryStream theMemStream = new MemoryStream();
            theMemStream.Write(attachmentData, 0, attachmentData.Length);
            theMemStream.Position = 0;

            try
            {
                //Upload attachment to SharePoint Online
                bool overwrite = Settings.Default.Overwrite;
                using (ClientContext clientContext = ClaimClientContext.GetAuthenticatedContext(Settings.Default.SharePointSiteUrl))
                {
                    var web = clientContext.Web;
                    var list = web.Lists.GetByTitle(Settings.Default.SharePointFolder);

                    var newFileFromComputer = new FileCreationInformation
                    {
                        Content = attachmentData,
                        Url = attachment.FileName
                    };

                    var uploadedFile = list.RootFolder.Files.Add(newFileFromComputer);
                    clientContext.Load(uploadedFile);
                    clientContext.RequestTimeout = 360000000;
                    clientContext.ExecuteQuery(); 
                }

                //Add Link for attachment
                mailItem.HTMLBody += Settings.Default.SharePointSiteUrl + Settings.Default.SharePointFolder +
                                     attachment.FileName + Environment.NewLine;

                //Delete attachement from mail message
                mailItem.Attachments.Remove(attachment.Index);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
    }

注意： 我对VSTO没有任何经验。