I have tried to work with poise but can't get it to work.

[rejafdofs]

///example
#[poise::command(slash_command, prefix_command)]
async fn mogetama(
    ctx:poise::Context<'a, Data, Box<dyn std::error::Error + Send + Sync>>,
) -> Result<(), Error> {
  let context = match ctx {
                poise::Context::Application(x) => x.serenity_context,
                poise::Context::Prefix(y) => y.serenity_context,
            };
             let a=songbird::get(context)
        .await

    Ok(())
}

If you do this, a will always be set to none when the user is in the voice channel.
Is it possible to use a bot created with poise?

[flashgnash]

Isn't serenity_context a function not a property?

#[poise::command(slash_command, prefix_command)]
async fn join_vc(ctx: Context<'_>) -> Result<(), Error> {

    let (guild_id, channel_id) = {
        let guild = ctx.guild().unwrap();
        let channel_id = guild
            .voice_states
            .get(&ctx.author().id)
            .and_then(|voice_state| voice_state.channel_id);

        (guild.id, channel_id)
    };

    let connect_to = match channel_id {
        Some(channel) => channel,
        None => {
            ctx.reply("Not in a voice channel").await;

            return Ok(());
        },
    };

    let manager = songbird::get(ctx.serenity_context())
        .await
        .expect("Songbird Voice client placed in at initialisation.")
        .clone();

    if let Ok(handler_lock) = manager.join(guild_id, connect_to).await {
        // Attach an event handler to see notifications of all track errors.
        println!("Success!");
    }
  
        
    Ok(())
}

Using this (join command example modified to work with poise) I've managed to get the bot to connect to a voice channel with no issue

[GnomedDev]

If songbird::get(ctx) is returning None, that means you have not called register_songbird on the serenity::ClientBuilder as the documentation says to do.

In future, please ask for help in the serenity-rs discord server.