How to post message in MS Teams using Graph API

Question

I am trying to send messages to MS Teams using Graph API using the following code.

 List<Recipient> recipients = new List<Recipient>();
        recipients.Add(new Recipient
        {
            EmailAddress = new EmailAddress
            {
                Address = "[email protected]"
            }
        });

        // Create the message.
        Message msg = new Message
        {
            Body = new ItemBody
            {
                Content = "Test message3",
                ContentType = BodyType.Text,
            },
            ToRecipients = recipients
        };

        _graphServiceClient.Users["fe0bb333-3334c49-a3eb-25af61fed1db"].SendMail(msg, true).Request().PostAsync().Wait();

This code does not send message in MS Team but instead send that message in email.

I am following the documentation https://learn.microsoft.com/en-us/graph/api/message-send?view=graph-rest-1.0 and was tyring Graph Explorer to send message but not working.

Post: https://graph.microsoft.com/v1.0/users/fe0bb333-3335-4c49-a3eb-25af61fed1db/messages/22229b36-a7cb-4a33-a9f9-dd75742bf067/send

Request Body

{ "Body": "Hello World" }

But, I get following error from Graph Explorer:

{
    "error": {
        "code": "ErrorInvalidIdMalformed",
        "message": "Id is malformed.",
        "innerError": {
            "request-id": "9cddabed-f886-4c89-be8b-7b5735ad957f",
            "date": "2019-04-21T05:37:11"
        }
    }
}

Answer 1

The Teams API allows creating new chats, as well as sending messages to existing ones.

Create a new chat object

Send messages to existing chats

List chats to retrieve the ID of an existing chat

Other options

If you're agnostic to how you send messages to users, you may be interested in sending proactive messages and proactive messaging for bots.