postMessage.cs

 internal async Task PostPhotoAsync(Photo instance)
        {
            try
            {
                var getById = _parser.GetById();
                var descrs = _parser.GetDescription();
                for (var i = 0; i < getById.Count && i < descrs.Count; i++)
                {
                    string photo = getById[i];
                    var descr = descrs[i];

                    using (var source = new CancellationTokenSource(7000))
                    using (var resp = await _client.GetStreamAsync(photo))
                    {
                        var msg = await _bot.SendPhotoAsync(
                            chatId: ChannelId,
                            photo: new InputOnlineFile(resp, "lol-community.jpg"),
                            replyMarkup: new InlineKeyboardMarkup(new[] {
                                new[] {
                                    new InlineKeyboardButton {Text = "👍 0", CallbackData = "post_id like"},
                                    new InlineKeyboardButton {Text = "👎 0", CallbackData = "post_id dislike"},
                                },
                            }),
                            caption: descr,
                            cancellationToken: new CancellationTokenSource().Token);

                        var postData = new PostData() {
                            Post_url = photo,
                            PostId = instance.PostId,
                            MessageId = msg.MessageId,
                            Likes = 0,
                            DisLikes = 0
                        };

                        _context.Posts.Add(postData);
                        _context.SaveChanges();
                    }
                }
            }
            catch (Exception e)
            {
                _logger.LogError(e.ToString());
            }
        }

        internal async Task PostVideoAsync(Video instance)
        {
            try
            {
                var descrs = _parser.GetVideoDescriptionList();
                var urls = _parser.GetVideoUrl();
                for (int i = 0; i < urls.Count; i++)
                {
                    var descr = descrs[i];
                    var video = urls[i];
                    var uri = new Uri(video);
                    if (uri.Host == "www.youtube.com" || uri.Host == "www.youtu.be")
                    {
                        var newUri =
                            $"https://youtube.com/watch?v={uri.LocalPath.Split('/')[2]}";
                        var msg = await _bot.SendTextMessageAsync(
                            chatId: ChannelId,
                            parseMode: ParseMode.Html,
                            text: "🎬 " + $"<b>{descr}*</b>" + Environment.NewLine +
                                  newUri, // made escape
                            replyMarkup: new InlineKeyboardMarkup(new[] {
                            new[] {
                                new InlineKeyboardButton {
                                    Text = "👍", CallbackData = "post_id like"
                                },
                                new InlineKeyboardButton {
                                    Text = "👎", CallbackData = "post_id dislike"
                                },
                            },
                            }),
                            cancellationToken: new CancellationTokenSource().Token);
                        var videoData = new PostData()
                        {
                            Post_url = video,
                            PostId = instance.Id,
                            MessageId = msg.MessageId,
                            Likes = 0,
                            DisLikes = 0
                        };

                        using (_context)
                        {
                            _context.Posts.Add(videoData);
                            _context.SaveChanges();
                        }
                    }
                }
            } catch (Exception e)
            {
                _logger.LogError(e.ToString());
            }
        }
    }