Save mail to msg file using EWS API

Question

I\'m using Exchange Web Services Managed API 1.1 to connect to Exchange server 2010 and then find out new emails received. Now I want to save a copy of the .msg file to a fo

Answer 1

You can easily access the MIME contents of the message through message.MimeContent and save the message as an EML file. The latest (2013 and 2016) versions of Outlook will be able to open EML files directly.

message.Load(new PropertySet(ItemSchema.MimeContent));
MimeContent mimcon = message.MimeContent;
FileStream fStream = new FileStream("c:\test.eml", FileMode.Create);
fStream.Write(mimcon.Content, 0, mimcon.Content.Length);
fStream.Close();

If you still need to convert to the MSG format, you have a few options:

1) MSG file format is documented - it is an OLE store (IStorage) file. See https://msdn.microsoft.com/en-us/library/cc463912(v=exchg.80).aspx

2) Use a third party MSG file wrapper, such as the one from Independentsoft: http://www.independentsoft.de/msg/index.html. Setting all properties that Outlook expects can be challenging.

3) Convert EML file to MSG directly using Redemption:

set Session = CreateObject("Redemption.RDOSession")
set Msg = Session.CreateMessageFromMsgFile("c:\test.msg")
Msg.Import("c:\test.eml", 1024)
Msg.Save

Answer 2

If you are happy to save into the .eml format instead, it can be done very easily just using EWS and no third party libraries. The .eml file will contain all the same information and can be opened by Outlook in the same way as .msg (and also by other programs).

message.Load(new PropertySet(ItemSchema.MimeContent));

MimeContent mc = message.MimeContent;
FileStream fs = new FileStream("c:\test.eml", FileMode.Create);

fs.Write(mc.Content, 0, mc.Content.Length);
fs.Close();

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Cleaned up code:

message.Load(new PropertySet(ItemSchema.MimeContent));
var mimeContent = message.MimeContent;

using (var fileStream = new FileStream(@"C:\Test.eml", FileMode.Create))
{
    fileStream.Write(mimeContent.Content, 0, mimeContent.Content.Length);
}