CommandHandler.cs

 private async Task HandleCommand(SocketMessage messageParam)
        {
            var message = messageParam as SocketUserMessage;
            if (message == null) return;

            var argPos = 0;

            if (!(message.HasCharPrefix('.', ref argPos) ||
                  message.HasMentionPrefix(_discord.CurrentUser, ref argPos)) || message.Author.IsBot) return;

            var context = new SocketCommandContext(_discord, message);
            var result = await _commands.ExecuteAsync(context, argPos, null);
        }