Wtelegramclient to listen for updates from only one channel and send the mesage to anoter

Question

How do I modify the standard example( https://github.com/wiz0u/WTelegramClient/blob/master/Examples/Program_ListenUpdates.cs ) given for WTelegramclient to listen for new messages and update from only one channel and send messages/or edits to another channel. Currently, it listens for messages from all channels or contacts to the user account is connected to.

1. Get and Listen for updates(news messages and edits) from only one channel.

2. Send the updates to another channel

    using System;
    using System.Collections.Generic;
    using System.Threading.Tasks;
    using TL;
   
    namespace WTelegramClientTest
    {
      static class Program_ListenUpdates
    {
      static WTelegram.Client Client;
      static User My;
      static readonly Dictionary<long, User> Users = new();
      static readonly Dictionary<long, ChatBase> Chats = new();
   
   // go to Project Properties > Debug > Environment variables and add at least these: 
   api_id, api_hash, phone_number
   static async Task Main(string[] _)
   {
       Console.WriteLine("The program will display updates received for the logged-in user. Press any key to terminate");
       WTelegram.Helpers.Log = (l, s) => System.Diagnostics.Debug.WriteLine(s);
       Client = new WTelegram.Client(Environment.GetEnvironmentVariable);
       using (Client)
       {
           Client.OnUpdate += Client_OnUpdate;
           My = await Client.LoginUserIfNeeded();
           Users[My.id] = My;
           // Note: on login, Telegram may sends a bunch of updates/messages that 
           happened in the past and were not acknowledged
           Console.WriteLine($"We are logged-in as {My.username ?? My.first_name + " " 
   + My.last_name} (id {My.id})");
           // We collect all infos about the users/chats so that updates can be printed with their names
           var dialogs = await Client.Messages_GetAllDialogs(); // dialogs = groups/channels/users
           dialogs.CollectUsersChats(Users, Chats);
           Console.ReadKey();
       }
   }
   
   // if not using async/await, we could just return Task.CompletedTask
   private static async Task Client_OnUpdate(IObject arg)
   {
       if (arg is not UpdatesBase updates) return;
       updates.CollectUsersChats(Users, Chats);
       foreach (var update in updates.UpdateList)
           switch (update)
           {
               case UpdateNewMessage unm: await DisplayMessage(unm.message); break;
               case UpdateEditMessage uem: await DisplayMessage(uem.message, true); break;
               // Note: UpdateNewChannelMessage and UpdateEditChannelMessage are also handled by above cases
               case UpdateDeleteChannelMessages udcm: Console.WriteLine($"{udcm.messages.Length} message(s) deleted in {Chat(udcm.channel_id)}"); break;
               case UpdateDeleteMessages udm: Console.WriteLine($"{udm.messages.Length} message(s) deleted"); break;
               case UpdateUserTyping uut: Console.WriteLine($"{User(uut.user_id)} is {uut.action}"); break;
               case UpdateChatUserTyping ucut: Console.WriteLine($"{Peer(ucut.from_id)} is {ucut.action} in {Chat(ucut.chat_id)}"); break;
               case UpdateChannelUserTyping ucut2: Console.WriteLine($"{Peer(ucut2.from_id)} is {ucut2.action} in {Chat(ucut2.channel_id)}"); break;
               case UpdateChatParticipants { participants: ChatParticipants cp }: Console.WriteLine($"{cp.participants.Length} participants in {Chat(cp.chat_id)}"); break;
               case UpdateUserStatus uus: Console.WriteLine($"{User(uus.user_id)} is now {uus.status.GetType().Name[10..]}"); break;
               case UpdateUserName uun: Console.WriteLine($"{User(uun.user_id)} has changed profile name: @{uun.username} {uun.first_name} {uun.last_name}"); break;
               case UpdateUserPhoto uup: Console.WriteLine($"{User(uup.user_id)} has changed profile photo"); break;
               default: Console.WriteLine(update.GetType().Name); break; // there are much more update types than the above cases
           }
   }
   
   // in this example method, we're not using async/await, so we just return Task.CompletedTask
   private static Task DisplayMessage(MessageBase messageBase, bool edit = false)
   {
       if (edit) Console.Write("(Edit): ");
       switch (messageBase)
       {
           case Message m: Console.WriteLine($"{Peer(m.from_id) ?? m.post_author} in {Peer(m.peer_id)}> {m.message}"); break;
           case MessageService ms: Console.WriteLine($"{Peer(ms.from_id)} in {Peer(ms.peer_id)} [{ms.action.GetType().Name[13..]}]"); break;
       }
       return Task.CompletedTask;
   }
   
   private static string User(long id) => Users.TryGetValue(id, out var user) ? user.ToString() : $"User {id}";
   private static string Chat(long id) => Chats.TryGetValue(id, out var chat) ? chat.ToString() : $"Chat {id}";
   private static string Peer(Peer peer) => peer is null ? null : peer is PeerUser user ? User(user.user_id)
       : peer is PeerChat or PeerChannel ? Chat(peer.ID) : $"Peer {peer.ID}";
   

   } }

Answer 1

Modify the DisplayMessage method similarly to: How to work with messages from WTelegramClient updates? (get chat/user infos)

You can check m.Peer.ID to react only to a specific channel ID

To forward a message somewhere else, follow this example