MediaPlayer Issue _mediaPlayer.Prepared += (sender, args) => {

I have an Issue in Android version(8.0 and above),in all other versions it's working fine,i have posted my code please check and help me in this case thank you

public void Play(string pathToAudioFile)
{
if (_mediaPlayer != null)
{
_mediaPlayer.Completion -= MediaPlayer_Completion;
_mediaPlayer.Stop();
}

        if (pathToAudioFile != null)
        {
            if (_mediaPlayer == null)
            {
                _mediaPlayer = new MediaPlayer();

                _mediaPlayer.Prepared += (sender, args) =>
                {
                    _mediaPlayer.Start();
                    _mediaPlayer.Completion += MediaPlayer_Completion;
                };**//it's not firing in oreo **
            }

            _mediaPlayer.Reset();
            //_mediaPlayer.SetVolume (1.0f, 1.0f);

            _mediaPlayer.SetDataSource(pathToAudioFile);
            _mediaPlayer.Start();
            _mediaPlayer.PrepareAsync();
        }
    }