How to get the response from the keyboard input in telegram bot? – Telegram API

To create a custom keyboard you have to sent a text message and pass a IReplyMarkup. The selected option is sent as a message which can be handled in the OnMessage event. You can hide the custom keyboard when you set a ReplyKeyboardHide as reply markup.

Here is an example:

private const string FirstOptionText = "First option";
private const string SecondOptionText = "Second option";

private async void BotClientOnMessage(object sender, MessageEventArgs e)
{
    switch (e.Message.Text)
    {
        case FirstOptionText:
            await BotClient.SendTextMessageAsync(e.Message.Chat.Id, "You chose the first option", replyMarkup:new ReplyKeyboardHide());
            break;
        case SecondOptionText:
            await BotClient.SendTextMessageAsync(e.Message.Chat.Id, "You chose the second option", replyMarkup:new ReplyKeyboardHide());
            break;

        default:
            await BotClient.SendTextMessageAsync(e.Message.Chat.Id, "Hi, select an option!",
                replyMarkup: new ReplyKeyboardMarkup(new[]
                {
                    new KeyboardButton(FirstOptionText),
                    new KeyboardButton(SecondOptionText),
                }));
            break;
    }
}

Here is a chat with a custom keyboard:

Here is a chat where I clicked the first button:

I hope this helps!