Why does my D2009 exe produce emails with attachments named ATTnnnnn.DAT when the same source code compiled in D2007 produces emails with attachments correctly named with the original file name?
I am using the respective Indy libraries that come with D2007 and D2009. Not having the original file name on the attachment prevents users from being able to double click the attachment to open it (typically attachments are Excel spreadsheets).
Note: code is identical - just the compiler and Indy libraries vary. The attachment sent by the D2009 exe can be saved and renamed to say zzzz.xls and then opens correctly -- ie the email and attachment go through correctly -- it is just the email attachment file name that is messed up.
Someone suggested the attachment headers are corrupted. Has Indy been broken? The code to reproduce is stock standard code that can be found on many websites, but I can post if necessary. Thx in advance.
I have found the problem - please see the adug.com.au mailing list for exact details of the solution, but in summary -- the version of Indy that comes with D2009 (version 10.2.5) has 2 errors in the IdMessageClient.pas unit in two lines that set the name= and filename= in the attachment part processing (one line number is 1222 from memory and the other is a few lines earlier; sorry I am at home now; I fixed things this evening at work). The lack of these semi-colons causes the attachment header to be badly formed and Outlook generates a name of its own for the attachment.
The fix is to output a semi-colon ( ; ) before outputting the name= or filename= tokens. Then Indy needs to be rebuilt.
I compared the D2007 version of Indy (10.1.5) and can see it always puts the semi-colon at the end of the Content-Type line thus avoiding the problem that has crept into the version included with D2009.
I recommend updating to the current Tiburon snapshot (http://indy.fulgan.com/ZIP). The Indy version is 10.5.7 now.
I'm afraid you might just need to trace down into the indy code. Indy has had a number of bugs in the past so this might be the cause. If you trace in you should find it pretty quickly.
Has the IdAttachment.Filename property been set? It's possible that between the Indy versions they changed the way that Filename works.
The recommendations of Richard worked for me. I compared the message sources of a correct attachment and that of Indy. Put the semicolons behind Content-type and Content-disposition (around line 1220 indeed, and it works. Thank you Richard!
来源：https://stackoverflow.com/questions/92196/why-does-my-d2009-exe-produce-emails-with-attachments-named-attnnnnn-dat