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Posted 3 Jul 2005


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MAPIEx: Extended MAPI Wrapper

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4.93/5 (137 votes)
5 Dec 2009CDDL7 min read
A (hopefully) complete extended MAPI wrapper for WinXP, WinCE, and .NET


I've been using simple MAPI for years, and recently, I had to send some mail programmatically and was reminded of the dreaded Outlook security warnings. So, I decided to look into the extended MAPI. What I found was a huge collection of samples that did one thing or another, but nothing that really did everything related to messages that I needed. This class, hopefully, covers everything an average user would need to do, including sending and receiving mail including attachments, multiple recipients, CC, BCC, etc. I did not put any code to manipulate information stores or services. See the example CMapiAdmin on CodeProject for this functionality. I've also tested this class using Unicode as well as ANSI strings.

Using CMapiEx

I've included the sample TestMAPI (link above) to show two cases. The project has been updated to Visual Studio 8 (2005), but I believe could be adapted to nearly every version of Visual Studio and Embedded Visual Studio. It's been tested in WinXP using Office 2003, and on Windows Mobile 2003. With a small amount of work removing the MFC code from the class (basically just CString), the class will work on Windows SmartPhone as well. Some of the newer code, including Outlook Forms support and AddressBook support is not supported in Windows Mobile.

To use the class, simply do the following:

  • Call CMAPIEx::Init() and Login() to initialize and login to MAPI.
  • Use OpenMessageStore() to open the desired store, i.e., "SMS"; (NULL for the default store).
  • To receive, call OpenInbox() and GetContents() followed by a looping GetNextMessage() call for each message (optionally reading in only the unread messages).
  • Use HasAttachment and SaveAttachments() to access the message's attachments.
void ReceiveTest(CMAPIEx& mapi)
    if(mapi.OpenInbox() && mapi.GetContents()) {
        CMAPIMessage message;
        while(mapi.GetNextMessage(message,TRUE)) {
            printf("Message from '%s' subject '%s'\n", 
            if(message.HasAttachments()) {
                printf("saving attachments...");

To send, call OpenOutbox() and CMapiMessage::Create(). Then, set the message properties, and then call CMapiMessage::Send():

void SendTest(CMAPIEx& mapi)
    if(mapi.OpenOutbox()) {
        CMAPIMessage message;
        if(message.Create(&mapi,IMPORTANCE_LOW)) {


            if(message.Send()) printf("Sent Successfully");

Use Logout() and CMAPIEx::Term() to exit MAPI. Obviously, if you want to try CMAPIEx in a Unicode project, you'll have to use wprintf instead.

RTF/HTML Support

A lot of people requested support for HTML messages. After doing a bunch of research and testing, I found that HTML is actually usually stored in the PR_RTF_COMPRESSED property, and that it can be decoded into HTML if it contains the text \\fromhtml. Thanks to Lucian Wischik for his example, the decoding code in MAPIEx is basically lifted right from his example (see the source for the address). I took it a step further by allowing you to set the RTF property with HTML in order to send an HTML email. Take a look at the SetRTF example in the sample TestMAPI project above, for more details.

.NET Wrapper for CMAPIEx

I originally wrote the NetMAPI wrapper as a proof of concept; it has little functionality beyond the basics. However over the last few months, I received so many questions and requests for enhancements for .NET that I have completely rewritten NetMAPI to be a thin layer above the Win32 DLL, CMAPIEx. NetMAPI offers support for nearly every feature provided in the C++ interface. The included sample above contains a .NET console project, TestNetMAPI, illustrating its usage.

To use the wrapper, first make sure your program has a reference to NetMAPI, and that the compiled MAPIEx.dll is in your output folder or in your path. Then, use NetMAPI.Init() and Login functions to access it:

if(NetMAPI.Init()) {
    NetMAPI mapi=new NetMAPI();
    if(mapi.Login()) {
        // Do some MAPI stuff here...

To receive in .NET (assumes you've logged in successfully):

  • Open the message store you want to access
  • Then open the inbox and get the contents table
  • Iterate through the message using GetNextMessage
  • Don't forget to Dispose of the message when you're finished with it!
public static void ReceiveTest(NetMAPI mapi)
    if(mapi.OpenInbox() && mapi.GetContents()) {

        MAPIMessage message;
        StringBuilder s=new StringBuilder(NetMAPI.DefaultBufferSize);
        while(mapi.GetNextMessage(out message,true)) {
            Console.Write("Message from '");
            Console.Write(s.ToString()+"' (");
            Console.Write(s.ToString()+"), subject '");
            Console.Write(s.ToString()+"', received: ");
            message.GetReceivedTime(s,"%m/%d/%Y %I:%M %p");
            // use message.GetBody() to get the ANSI text body
            // use message.GetRTF() to get the RTF or decoded HTML email

To send a message (assumes you've logged in successfully):

  • Open the message store you want to access
  • Open the outbox
  • Create a new message, set its priority if you like
  • Set its properties, recipients and attachments
  • Call Send
public static void SendTest(NetMAPI mapi)
    if(mapi.OpenOutbox()) {
        MAPIMessage message=new MAPIMessage();
        if(message.Create(mapi,MAPIMessage.Priority.IMPORTANCE_LOW)) {

            // user SetBody for ANSI text, SetRTF for HTML and Rich Text

            if(message.Send()) Console.WriteLine("Sent Successfully");

See the ContactsTest and FoldersTest functions in TestNetMAPI for more examples.

Use the Logout and NetMAPI.Term() call to close the wrapper. To use Unicode, compile CMAPIEx with Unicode set, and change the DefaultCharSet variable in NetMAPI to CharSet.Unicode.

Future Improvements

I'd like to add more support for Calendar and Task items. Outlook 2010 support is another thing coming down the pipeline, currently no tests have been done.

I couldn't figure out how to create a One-Off EntryID in Windows Mobile, as the IAddressBook interface is not implemented. This has the annoying effect of not sending the outgoing emails on these devices until you manually open the message in your Outbox and hit Send. If anyone knows how this is done, please let me know, and I will update it.

This code is free to use as long as the copyright notice remains at the top of the file and any enhancements or bug fixes are posted here for the community. I hope it helps someone skip the pain I went through!


  • 07/01/2005 - Initial release
  • 07/13/2005 - Small bug fixes and additions, see below for details
  • 08/25/2005 - Small modifications and a .NET wrapper (see below)
  • 01/27/2006 - Added a bunch of new commands for handling folders and messages (see below)
  • 05/16/2006 - Added RTF and HTML support
  • 06/02/2006 - Added external folder support, and fixed a couple of small bugs (thanks to all who reported the issues)
  • 08/21/2006 - Reorganized files, added support for reading contacts, notifications, and fixed some minor bugs
  • 10/02/2006 - Complete rewrite of the .NET wrapper, with full MAPIEx access from .NET
  • 11/01/2006 - Added support for many new fields, added IMessage Form support and writeable contacts
  • 12/04/2009 - Enhanced performance, completed contacts and added rudimentary Calendar support

Detailed History

  • Fixed a bug with attachments (thanks alan, see forum below for details).
  • While in the attachment code, I modified PR_ATTACH_FILENAME to be the filename of the attachment instead of the full path.
  • Added support for Outlook 2000. To use this class with Outlook 2000, you must call CMAPIEx::Init with a value of zero instead of the default MAPI_UNICODE. Also, building the project for Unicode doesn't work with Office 2000 as far as I can tell (it responds with ANSI strings).
  • Fixed the "mail stays in Outbox after it's sent" problem. See the posting below for more info.
  • Added a priority field to CMAPIMessage::Create, you can now optionally set IMPORTANCE_LOW or IMPORTANCE_HIGH.
  • You can now call AddRecipient repeatedly to send to more than one user.
  • Updated project to Visual Studio 2008.
  • Added a post build step to copy MAPIEx.dll to the test projects' output folders.
  • Added subfolder support to the DLL, you can now iterate through and directly open subfolders.
  • Modified the Login command to take a profile name (thanks Chris, see forum for details).
  • Added the GetProfileName command to find out what the current profile's name is (thanks Jason, author of CMAPIAdmin).
  • Added the ReceivedTime property and the GetReceivedTime function to the message class (thanks again Chris, see forum).
  • Added a CopyMessage function to copy a message between folders as well as the DeleteMessage and MoveMessage functions.
  • Added the CreateSubFolder, DeleteSubFolder functions.
  • Added a OpenSentItems function.
  • Added a new RTF property, this allows us to set RTF text and even HTML (see TestMAPI, for an example).
  • Changed GetBody and GetRTF to be filled on demand rather than when opening the message.
  • MAPIEx can now extract SMTP email addresses from Exchange (EX) native addresses (see FillSenderEmail, for details).
  • MAPIEx can now receive notifications from MAPI (i.e., for new mail arrivals, message deletion etc., see NotificationTest for an example.
  • Added read only support for contacts, see ContactsTest for a sample).
  • Fixed a bug with bad strings from MAPI properties (see GetValidString for more info).
  • Added support for the MAPI_NO_CACHE flag (for Outlook 2003).
  • Added the OpenContacts and OpenDrafts functions.
  • Added a GetRowCount for providing progress feedback for long folder operations.
  • Added support for the AddressList form to get a list of recipients via the common UI. (C++ only, C# if people request it.)
  • Added support for custom Named Properties in Contacts and Messages.
  • Added IMessageForm support to show the default form for editing messages.
  • Added Save, SubmitTime, Sensitivity, MessageFlags, and DeliveryReceipt properties to messages.
  • Added support for enumerating recipients of a message.
  • MAPIContact now supports the three email fields.
  • Added many new fields to contacts such as Company, HomePage, DisplayAs, etc.
  • Added support for creating contacts.
  • Added rudimentary Calendar support (no create appointment functionality yet).
  • Added extensive folder support, see FolderTest for an example.
  • Added CreateProfile and DeleteProfile because of multiple requests.
  • Extended RTF and HTML support, added GetMessageEditorFormat to detect formats.
  • Many small improvements and additions requested by the userbase (too many to list, see forum below for details).


This article, along with any associated source code and files, is licensed under The Common Development and Distribution License (CDDL)


About the Author

Noel Dillabough
Software Developer (Senior)
Canada Canada
No Biography provided

Comments and Discussions

QuestionHow can I create more than 1 email drafts and show them in different dialogs? Pin
JETONE4-Jul-20 9:40
MemberJETONE4-Jul-20 9:40 
QuestionIs working ? Pin
David Desiderà20-May-19 0:34
MemberDavid Desiderà20-May-19 0:34 
Questionalways fail on OpenMessageStore Pin
ShenXiaoLong18-Mar-18 19:43
MemberShenXiaoLong18-Mar-18 19:43 
QuestionMS Exchange 2016 & MAPI. Will it continue to work? Pin
Member 1295450317-Jan-17 4:47
MemberMember 1295450317-Jan-17 4:47 
QuestionMAPI extended HTML Body Pin
Member 1227806015-Apr-16 3:39
MemberMember 1227806015-Apr-16 3:39 
AnswerRe: MAPI extended HTML Body Pin
Kees van Spelde22-Jun-16 1:52
professionalKees van Spelde22-Jun-16 1:52 
GeneralMy vote of 3 Pin
Member 1227806015-Apr-16 3:33
MemberMember 1227806015-Apr-16 3:33 
QuestionWin10 (64bit), VS2013, Outlook 2010 (32Bit): AccessViolationException MAPIObject.Dispose Pin
Ole Ketelsen24-Nov-15 3:49
MemberOle Ketelsen24-Nov-15 3:49 
QuestionTrouble to empty trash folder on win 7 64 bit Pin
Omega Doe15-Sep-15 22:41
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AnswerRe: Trouble to empty trash folder on win 7 64 bit Pin
Noel Dillabough16-Sep-15 1:12
MemberNoel Dillabough16-Sep-15 1:12 
QuestionHow to get/connect to an open email? Pin
MrNoWords5-Jun-15 5:00
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QuestionMAPI replacing /r/n by "ne" from Mailbox. Pin
RANJAN DAS14-May-15 0:18
MemberRANJAN DAS14-May-15 0:18 
BugCannot save bitmap after e-mail Pin
Siddiqui's6-May-15 3:58
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BugIntermittent reliability when used with multiple threads and multiple recipient addresses Pin
MrWhiteboard15-Apr-15 11:23
MemberMrWhiteboard15-Apr-15 11:23 
GeneralRe: Intermittent reliability when used with multiple threads and multiple recipient addresses Pin
Noel Dillabough15-Apr-15 11:26
MemberNoel Dillabough15-Apr-15 11:26 
GeneralRe: Intermittent reliability when used with multiple threads and multiple recipient addresses Pin
MrWhiteboard16-Apr-15 9:12
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Question[VS2008, Outlook 2010, Unicode] HTML Body not set Pin
svallant9-Mar-15 3:10
Membersvallant9-Mar-15 3:10 
AnswerRe: [VS2008, Outlook 2010, Unicode] HTML Body not set Pin
Noel Dillabough9-Mar-15 3:45
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GeneralRe: [VS2008, Outlook 2010, Unicode] HTML Body not set Pin
svallant15-Mar-15 21:10
Membersvallant15-Mar-15 21:10 
GeneralRe: [VS2008, Outlook 2010, Unicode] HTML Body not set Pin
Noel Dillabough18-Mar-15 13:44
MemberNoel Dillabough18-Mar-15 13:44 
GeneralRe: [VS2008, Outlook 2010, Unicode] HTML Body not set Pin
svallant22-Mar-15 21:48
Membersvallant22-Mar-15 21:48 
GeneralRe: [VS2008, Outlook 2010, Unicode] HTML Body not set Pin
Noel Dillabough23-Mar-15 2:29
MemberNoel Dillabough23-Mar-15 2:29 
QuestionCrossing the x86/x64/AnyCPU divide. Pin
Phil Sayers22-Jan-15 4:23
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AnswerRe: Crossing the x86/x64/AnyCPU divide. Pin
Noel Dillabough22-Jan-15 4:41
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GeneralRe: Crossing the x86/x64/AnyCPU divide. Pin
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