C#.NET No.25-3

if (windowDialog.FileName.EndsWith(".mp3"))
{
    NAudio.Wave.WaveStream pcm = NAudio.Wave.WaveFormatConversionStream.CreatePcmStream(new NAudio.Wave.Mp3FileReader(windowDialog.FileName));
    stream = new NAudio.Wave.BlockAlignReductionStream(pcm);
}
else if (windowDialog.FileName.EndsWith(".wav"))
{
    NAudio.Wave.WaveStream pcm = new NAudio.Wave.WaveChannel32(new NAudio.Wave.WaveFileReader(windowDialog.FileName));
    stream = new NAudio.Wave.BlockAlignReductionStream(pcm);
}
else throw new InvalidOperationException("Not supported file");