How to send a voice note file to a Telegram group in C# using Visual Studio 2019

This article shows you how to send a voice note file (e.g. an OPUS file) to a registered Telegram group in Microsoft’s .NET language: C# using Visual Studio 2019.

If you are using Visual Studio 2022, please read this tutorial instead.

To send a Telegram message containing a voice note file in C# using Visual Studio 2019, do this:

First, learn how to send a simple text message to a group on the official site.
With the above knowledge, you can now download our sample code.

Locate the file cs/group-send-telegram-opus.cs.

	using System;
	using System.Net;
	using System.Web.Script.Serialization; // requires the reference 'System.Web.Extensions'
	using System.IO;
	using System.Text;

	class TelegramGroupOpusSender
	{
	// TODO: Replace the following with your gateway instance ID, client ID and secret!
	private static string INSTANCE_ID = "YOUR_INSTANCE_ID";
	private static string CLIENT_ID = "YOUR_CLIENT_ID_HERE";
	private static string CLIENT_SECRET = "YOUR_CLIENT_SECRET_HERE";

	private static string VOICE_GROUP_API_URL = "https://api.whatsmate.net/v3/telegram/group/voice_note/message/" + INSTANCE_ID;

	static void Main(string[] args)
	{
	TelegramGroupOpusSender opusSender = new TelegramGroupOpusSender();

	// TODO: Put down group name and group admin below
	string group_name = "Muscle Men Club";
	string group_admin = "19159876123";

	// TODO: Remember to copy the OPUS file from ..\assets to the TEMP directory!
	string base64Content = convertFileToBase64("C:\\TEMP\\martin-luther-king.opus");
	string fn = "anyname.opus";
	string caption = "I have a dream";

	opusSender.sendVoiceNoteToGroup(group_name, group_admin, base64Content, fn, caption);

	Console.WriteLine("Press Enter to exit.");
	Console.ReadLine();
	}

	// http://stackoverflow.com/questions/25919387/c-sharp-converting-file-into-base64string-and-back-again
	static public string convertFileToBase64(string fullPathToDoc)
	{
	Byte[] bytes = File.ReadAllBytes(fullPathToDoc);
	String base64Encoded = Convert.ToBase64String(bytes);
	return base64Encoded;
	}

	public bool sendVoiceNoteToGroup(string group_name, string group_admin, string base64Content, string fn, string caption)
	{
	bool success = true;

	try
	{
	using (WebClient client = new WebClient())
	{
	client.Headers[HttpRequestHeader.ContentType] = "application/json";
	client.Headers["X-WM-CLIENT-ID"] = CLIENT_ID;
	client.Headers["X-WM-CLIENT-SECRET"] = CLIENT_SECRET;

	GroupVoicePayload payloadObj = new GroupVoicePayload() { group_name = group_name, group_admin = group_admin, voice_note = base64Content, filename = fn, caption = caption};
	string postData = (new JavaScriptSerializer()).Serialize(payloadObj);

	client.Encoding = Encoding.UTF8;
	string response = client.UploadString(VOICE_GROUP_API_URL, postData);
	Console.WriteLine(response);
	}
	}
	catch (WebException webEx)
	{
	Console.WriteLine(((HttpWebResponse)webEx.Response).StatusCode);
	Stream stream = ((HttpWebResponse)webEx.Response).GetResponseStream();
	StreamReader reader = new StreamReader(stream);
	String body = reader.ReadToEnd();
	Console.WriteLine(body);
	success = false;
	}

	return success;
	}

	public class GroupVoicePayload
	{
	public string group_name { get; set; }
	public string group_admin { get; set; }
	public string voice_note { get; set; }
	public string filename { get; set; }
	public string caption { get; set; }
	}

	}

view raw group-send-telegram-opus.cs hosted with ❤ by GitHub

Study the C# source code and customize the TODO/FIXME lines.
Run the C# program in Visual Studio to send your group your first OPUS file!

Happy coding :)