使用C＃以编程方式将OLE对象插入Outlook电子邮件

Question

I am trying to embed an Excel file into an Outlook email message. I am setting the attachment type to "OlAttachmentType.olOLE", however when the message is created, the Excel document arrives as an attachment.

Below is my code. It seems pretty straightforward, but it does not work as expected.

        var application = new Microsoft.Office.Interop.Outlook.Application();
        var message = (MailItem)application.CreateItem(OlItemType.olMailItem);
        var path = @"C:\Excel\Workbook.xlsx";
        var missing = System.Type.Missing;

        message.Attachments.Add(path, OlAttachmentType.olOLE, 1, missing);
        message.SaveAs(@"C:\Excel\Workbook.msg", OlSaveAsType.olMSG);

        application.Quit();

Answer 1

Outlook Object Model would not let you insert embedded OLE objects - the best you can do is access existing ones. Inserting OLE attachments is non-trivial even on the Extended MAPI level - you will need to create a specially formatted IStorage for the attachment, then populate its data in the format that only the host that will handle it later can understand. You will also need to provide the bitmap with the preview and insert the appropriate placeholder in the RTF body.