Full Example

On the previous page we got a basic bot reacting to messages via bot.OnMessage.

Now, we are going to set also bot.OnUpdate and bot.OnError to make a more complete bot

Modify your Program.cs to the following:

using Telegram.Bot;
using Telegram.Bot.Polling;
using Telegram.Bot.Types;
using Telegram.Bot.Types.Enums;
using Telegram.Bot.Types.ReplyMarkups;

using var cts = new CancellationTokenSource();
var bot = new TelegramBotClient("YOUR_BOT_TOKEN", cancellationToken: cts.Token);
var me = await bot.GetMe();
bot.OnError += OnError;
bot.OnMessage += OnMessage;
bot.OnUpdate += OnUpdate;

Console.WriteLine($"@{me.Username} is running... Press Enter to terminate");
Console.ReadLine();
cts.Cancel(); // stop the bot

// method to handle errors in polling or in your OnMessage/OnUpdate code
async Task OnError(Exception exception, HandleErrorSource source)
{
    Console.WriteLine(exception); // just dump the exception to the console
}

// method that handle messages received by the bot:
async Task OnMessage(Message msg, UpdateType type)
{
    if (msg.Text == "/start")
    {
        await bot.SendMessage(msg.Chat, "Welcome! Pick one direction",
            replyMarkup: new InlineKeyboardMarkup().AddButtons("Left", "Right"));
    }
}

// method that handle other types of updates received by the bot:
async Task OnUpdate(Update update)
{
    if (update is { CallbackQuery: { } query }) // non-null CallbackQuery
    {
        await bot.AnswerCallbackQuery(query.Id, $"You picked {query.Data}");
        await bot.SendMessage(query.Message!.Chat, $"User {query.From} clicked on {query.Data}");
    }
}

Run the program and send /start to the bot.

The bot will reply with its welcome message and 2 inline buttons for you to choose.

When you click on a button, your bot receives an Update of type CallbackQuery that is not a simple message.
Therefore it will be handled by OnUpdate instead.

We handle this by replying the callback data (which could be different from the button text), and which user clicked on it (which could be any user if the message was in a group)

The OnError method handles errors, and you would typically log it to trace problems in your bot.

Look at the Console example in our Examples repository for an even more complete bot code.