protected override async Task OnMembersAddedAsync(IList <ChannelAccount> membersAdded, ITurnContext <IConversationUpdateActivity> turnContext, CancellationToken cancellationToken) { foreach (var member in membersAdded) { // Greet anyone that was not the target (recipient) of this message. // To learn more about Adaptive Cards, see https://aka.ms/msbot-adaptivecards for more details. if (member.Id != turnContext.Activity.Recipient.Id) { var welcomeCard = CreateAdaptiveCardAttachment(); var response = MessageFactory.Attachment(welcomeCard); response.Speak = MainDialog.SSML("Hello from your pizza service. We bake the best Italian pizza in town! In Italy pizza falls into two distinct categories: Italian pizza and the rest of the world. You will never feel the same about this simple and delicious food again."); await turnContext.SendActivityAsync(response, cancellationToken); await Dialog.RunAsync(turnContext, ConversationState.CreateProperty <DialogState>("DialogState"), cancellationToken); } } }