TeamsBotTopLevelActivityWithMention.cs

using Microsoft.Bot.Builder;
using Microsoft.Bot.Connector;
using Microsoft.Bot.Connector.Authentication;
using Microsoft.Bot.Schema;
using Microsoft.Bot.Schema.Teams;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Teams.Bot.Conversations
{
    class Program
    {
        public static async Task Main(string[] args)
        {
            //Teams internal id
            string teamInternalId = "19:96391bb270744e218c04dc8f571d3d8b@thread.skype";

            //Teams channel id in which to create the post.
            string teamsChannelId = "19:86f8774fd88a4d4ba1bae4715dcca821@thread.skype";

            //The Bot Service Url needs to be dynamically stored and fetched from the Team. Recommendation is to store the serviceUrl from the bot Payload and later re-use it to send proactive messages.
            string serviceUrl = "https://smba.trafficmanager.net/emea/";

            //the upn of the user who should be mentioned.
            string mentionUserPrincipalName = "user@tenant.onmicrosoft.com";

            //From the Bot Channel Registration
            string botClientID = "<client-id>";
            string botClientSecret = "<client-secret>";

            MicrosoftAppCredentials.TrustServiceUrl(serviceUrl);
            var connectorClient = new ConnectorClient(new Uri(serviceUrl), new MicrosoftAppCredentials(botClientID, botClientSecret));

            var teamMembers = await connectorClient.Conversations.GetConversationMembersAsync(teamInternalId, default);
            var userToMention = teamMembers
                .Select(channelAccount => JObject.FromObject(channelAccount).ToObject<TeamsChannelAccount>())
                .First(user => user.UserPrincipalName == mentionUserPrincipalName);

            var mention = new Mention
            {
                Mentioned = userToMention,
                Text = $"<at>{userToMention.Name}</at>",
            };

            var topLevelMessageActivityWithMention = MessageFactory.Text($"Hi {mention.Text}");
            topLevelMessageActivityWithMention.Entities = new List<Entity> { mention };

            var conversationParameters = new ConversationParameters
            {
                IsGroup = true,
                ChannelData = new TeamsChannelData
                {
                    Channel = new ChannelInfo(teamsChannelId),
                },
                Activity = topLevelMessageActivityWithMention
            };

            await connectorClient.Conversations.CreateConversationAsync(conversationParameters);
        }
    }
}