How to Join Wav files in One Using C#

Question

I create a software to concatenate wav files into one I use this code

using Alvas.Audio;    
private void JoinWav()
{
    string[] files = new string[] { "file01_01.wav","file01_01.wav"};
    AudioCompressionManager.Join("res.wav", files);
}

It's working for me ,but i use trial of Alvas.Audio is there a way to create something like this free?