Discord.Net 2.0将消息发送到特定通道

using Discord;
using Discord.WebSocket;
using System;
using System.Threading.Tasks;

class Program
{
    private DiscordSocketClient _client;

    static void Main(string[] args)
    {
        new Program().RunBotAsync().GetAwaiter().GetResult();
    }

    public async Task RunBotAsync()
    {
        _client = new DiscordSocketClient();

        _client.Log += Log;

        await _client.LoginAsync(TokenType.Bot, "YOUR_BOT_TOKEN");

        await _client.StartAsync();

        _client.MessageReceived += HandleMessageReceived;

        // Keep the bot running until it is manually stopped
        await Task.Delay(-1);
    }

    private Task Log(LogMessage arg)
    {
        Console.WriteLine(arg);
        return Task.CompletedTask;
    }

    private async Task HandleMessageReceived(SocketMessage message)
    {
        if (message.Content.ToLower() == "!sendmessage")
        {
            // Get the channel to send the message to (replace CHANNEL_ID with the actual channel ID)
            var channel = _client.GetChannel(CHANNEL_ID) as SocketTextChannel;

            // Send the message to the channel
            await channel.SendMessageAsync("Hello, world!");
        }
    }
}