Building a Microsoft Teams Bot with Bot Framework

With Microsoft Teams usage skyrocketing during the pandemic, building bots for Teams has become increasingly valuable. Teams bots can automate workflows, answer questions, and integrate with business systems. Here is how to build one.

Prerequisites

• .NET Core 3.1 SDK
• Bot Framework SDK v4
• Azure subscription
• Microsoft Teams (for testing)

Creating the Bot Project

# Install the Bot Framework templates
dotnet new -i Microsoft.Bot.Framework.CSharp.EchoBot

# Create a new bot
dotnet new echobot -n MyTeamsBot

cd MyTeamsBot

Understanding the Bot Structure

The main bot class handles incoming activities:

using Microsoft.Bot.Builder;
using Microsoft.Bot.Builder.Teams;
using Microsoft.Bot.Schema;
using Microsoft.Bot.Schema.Teams;

public class TeamsBot : TeamsActivityHandler
{
    protected override async Task OnMessageActivityAsync(
        ITurnContext<IMessageActivity> turnContext,
        CancellationToken cancellationToken)
    {
        var text = turnContext.Activity.Text?.Trim().ToLower();

        switch (text)
        {
            case "help":
                await SendHelpCardAsync(turnContext, cancellationToken);
                break;
            case "status":
                await SendStatusAsync(turnContext, cancellationToken);
                break;
            default:
                var reply = $"You said: {turnContext.Activity.Text}";
                await turnContext.SendActivityAsync(
                    MessageFactory.Text(reply),
                    cancellationToken);
                break;
        }
    }

    protected override async Task OnMembersAddedAsync(
        IList<ChannelAccount> membersAdded,
        ITurnContext<IConversationUpdateActivity> turnContext,
        CancellationToken cancellationToken)
    {
        foreach (var member in membersAdded)
        {
            if (member.Id != turnContext.Activity.Recipient.Id)
            {
                await turnContext.SendActivityAsync(
                    MessageFactory.Text("Welcome to the team! Type 'help' to get started."),
                    cancellationToken);
            }
        }
    }
}

Building Adaptive Cards

Create rich interactive messages:

private async Task SendHelpCardAsync(
    ITurnContext turnContext,
    CancellationToken cancellationToken)
{
    var card = new AdaptiveCard(new AdaptiveSchemaVersion(1, 2))
    {
        Body = new List<AdaptiveElement>
        {
            new AdaptiveTextBlock
            {
                Text = "Teams Bot Help",
                Size = AdaptiveTextSize.Large,
                Weight = AdaptiveTextWeight.Bolder
            },
            new AdaptiveTextBlock
            {
                Text = "Available commands:",
                Wrap = true
            },
            new AdaptiveFactSet
            {
                Facts = new List<AdaptiveFact>
                {
                    new AdaptiveFact("help", "Show this help message"),
                    new AdaptiveFact("status", "Check system status"),
                    new AdaptiveFact("report", "Generate a report")
                }
            }
        },
        Actions = new List<AdaptiveAction>
        {
            new AdaptiveSubmitAction
            {
                Title = "Get Status",
                Data = new { action = "status" }
            }
        }
    };

    var attachment = new Attachment
    {
        ContentType = AdaptiveCard.ContentType,
        Content = card
    };

    await turnContext.SendActivityAsync(
        MessageFactory.Attachment(attachment),
        cancellationToken);
}

Handling Card Actions

protected override async Task<InvokeResponse> OnAdaptiveCardInvokeAsync(
    ITurnContext<IInvokeActivity> turnContext,
    AdaptiveCardInvokeValue invokeValue,
    CancellationToken cancellationToken)
{
    var action = invokeValue.Action?.Data?.ToString();
    var data = JsonConvert.DeserializeObject<CardActionData>(action);

    switch (data?.Action)
    {
        case "status":
            await SendStatusAsync(turnContext, cancellationToken);
            break;
    }

    return new InvokeResponse { Status = 200 };
}

public class CardActionData
{
    public string Action { get; set; }
}

Proactive Messages

Send messages without user interaction:

public class ProactiveMessageService
{
    private readonly IBotFrameworkHttpAdapter _adapter;
    private readonly string _appId;

    public async Task SendProactiveMessageAsync(
        ConversationReference reference,
        string message)
    {
        await ((BotAdapter)_adapter).ContinueConversationAsync(
            _appId,
            reference,
            async (turnContext, cancellationToken) =>
            {
                await turnContext.SendActivityAsync(message);
            },
            CancellationToken.None);
    }
}

Deploying to Azure

# Create a Bot Channels Registration
az bot create \
    --resource-group rg-bots \
    --name my-teams-bot \
    --kind registration \
    --sku F0 \
    --endpoint https://my-teams-bot.azurewebsites.net/api/messages

# Deploy the web app
az webapp up \
    --resource-group rg-bots \
    --name my-teams-bot \
    --runtime "DOTNETCORE:3.1"

Teams App Manifest

Create manifest.json for Teams:

{
    "$schema": "https://developer.microsoft.com/en-us/json-schemas/teams/v1.7/MicrosoftTeams.schema.json",
    "manifestVersion": "1.7",
    "version": "1.0.0",
    "id": "your-app-id",
    "packageName": "com.company.teamsbot",
    "developer": {
        "name": "Your Company",
        "websiteUrl": "https://example.com",
        "privacyUrl": "https://example.com/privacy",
        "termsOfUseUrl": "https://example.com/terms"
    },
    "name": {
        "short": "My Teams Bot",
        "full": "My Teams Bot for Automation"
    },
    "description": {
        "short": "A helpful bot for your team",
        "full": "This bot helps automate common tasks and provides quick access to information."
    },
    "icons": {
        "outline": "outline.png",
        "color": "color.png"
    },
    "bots": [
        {
            "botId": "your-bot-id",
            "scopes": ["personal", "team", "groupchat"],
            "commandLists": [
                {
                    "scopes": ["personal", "team"],
                    "commands": [
                        { "title": "help", "description": "Show help" },
                        { "title": "status", "description": "Check status" }
                    ]
                }
            ]
        }
    ]
}

Testing Locally

Use ngrok for local testing:

# Start ngrok
ngrok http 3978

# Update bot endpoint in Azure portal to ngrok URL
# https://xxxxx.ngrok.io/api/messages

Teams bots provide a powerful way to bring automation directly into the collaboration hub that many organizations now rely on daily.