using System;
using System.Text;
using System.Runtime.InteropServices;

namespace MP3
{
	public class MP3Player
	{
		private string _Alias;

		public MP3Player(string pAlias)
		{
			this._Alias=pAlias;
		}

		public bool Play(string pFileName)
		{
			bool ret=false;
			StringBuilder retApi=new StringBuilder(new string(' ',256));
			if(GetShortPathName(pFileName,retApi,retApi.Length)>0)
			{
				//MCI öffnen
				int intMciResult=mciSendString(string.Format("open {0} type MPEGVideo alias {1}",retApi.ToString(),this._Alias),string.Empty ,0,IntPtr.Zero);

				int intPlayResult=-1;
				if (intMciResult==0)
				{
					//MP3 Play
					intPlayResult=mciSendString(string.Format("play {0} from 0",this._Alias),string.Empty ,0,IntPtr.Zero);
				}

				ret=intPlayResult==0;
			}
			return ret;
		}

		public bool Stop()
		{
			bool ret=false;
			if(mciSendString(string.Format("stop {0}",this._Alias),string.Empty ,0,IntPtr.Zero)==0)
			{
				ret=mciSendString(string.Format("close {0}",this._Alias),string.Empty ,0,IntPtr.Zero)==0;
			}
			return ret;
		}
		[DllImport("winmm.dll")]
		private static extern int mciSendString (string lpCommand,string lpReturn, int nReturnLength,IntPtr callBack);

		[DllImport("kernel32")]
		private static extern int GetShortPathName(string lpLongPath, StringBuilder lpShortPath, int Buffer);
	}
}

MP3.MP3Player _M=new MP3.MP3Player("myPlayer");
		private void btnPlay_Click(object sender, System.EventArgs e)
		{
			this._M.Play(@"C:\..\xy.mp3");
		}

		private void btnStop_Click(object sender, System.EventArgs e)
		{
			this._M.Stop();
		}

using Microsoft.DirectX.AudioVideoPlayback;

...

string filename = "Song.mp3";
Audio audioPlayback = new Audio(filename);
audioPlayback.Play();

...

mciSendString(string.Format("play {0} from 0 notify",this._Alias),string.Empty ,0,this.Handle);

protected override void WndProc(ref Message m)
{
	base.WndProc (ref m);
	if (m.Msg==MM_MCINOTIFY)
	{
		//ich hatte hier ein Problem, dass er hier immer 2 mal reingelaufen ist 
		//mit einem ganz kurzen Thread.Sleep trat es nimmer auf
		Thread.Sleep(1);
		//schliessen
		mciSendString(string.Format("close {0}",this._Alias),string.Empty ,0,this.Handle);
		//Play Complete
	}
}	
}