I am posting an update/progress report here for future reference:

So, I have checked Outlook from Office 2010 Professional (14.0.7128.5000 - 32 bit) and MAPI_DIALOG_MODELESS is not supported in this version.

I downloaded the trial version of Outlook 2013 (15.0.4420.1017 - 32 Bit) and Outlook DOES support the MAPI_DIALOG_MODELESS flag for MapiSendMail().

However, there are issues as follows:

(1) No Attachments - works fine

(2) One attachment you MUST set the lpszFileName pointer within MapiFileDesc, you cannot leave it as NULL. If you leave it as NULL then MapiSendMail() returns MAPI_E_FAILURE.

(3) Two or more attachments - It always returns MAPI_E_FAILURE.

But for all cases above, if I replace MAPI_DIALOG_MODELESS with MAPI_DIALOG it works perfectly fine but the dialog is Modal which is not what I want.


Anyway, I am still trying to work this all out but it looks as if even though the MapiSendMailHelper() function contained solely within MapiUnicodeHelp.h passes the Modeless flag through after conversion to ANSI, I just have a gut feeling that on the Outlook side of things it is still assuming Widestrings for some of the information.

I have no proof but given that all I am doing is flicking a flag on/off I cannot think what else it could be.

So, any advice on where I go next to get this resolved - which Microsoft forum would be best to post in ?

Thanks in advance
Leslie.


On Tue, 12 Apr 2016 21:57:35 -0400, Leslie <[log in to unmask]> wrote:

>You are correct in that Simple MAPI itself appears not to have changed but there is a new flag introduced in the Windows 8 SDK for MapiSendMailHelper() and MapiSendMailW() which is  MAPI_DIALOG_MODELESS 0x0000000c.
>
>This potentially allows the Compose Mail dialog to be modeless if the email client itself supports it. MSDN tells me that Outlook 2013 supports it, so I am trying to find out if that is the first version of Outlook to do so or does Outlook 2010 also support it.
>
>I am also hoping that MAPISendMail() just passes the flag along as well because I really do not want to have to convert ANSI to Unicode just to use the MapiSendMailHelper() for a modeless dialog.
>

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