This code uses the Windows Multimedia API winmm.dll library to play MP3 files. Put it into a class and call the Open() method with a parameter specifying the MP3 file that you wish to play.

1. private string _command;
2. private bool isOpen;
3. [DllImport("winmm.dll")]
4. 
5. private static extern long mciSendString(string strCommand,StringBuilder strReturn,int iReturnLength, IntPtr hwndCallback);
6. 
7. public void Close()
8. {
9.     _command = "close MediaFile";
10.    mciSendString(_command, null, 0, IntPtr.Zero);
11.    isOpen = false;
12. }
13. 
14. public void Open(string sFileName)
15. {
16.    _command = "open \"" + sFileName + "\" type mpegvideo alias MediaFile";
17.    mciSendString(_command, null, 0, IntPtr.Zero);
18.    isOpen = true;
19. }
20. 
21. public void Play(bool loop)
22. {
23.    if(isOpen)
24.    {
25.       _command = "play MediaFile";
26.       if (loop)
27.        _command += " REPEAT";
28.       mciSendString(_command, null, 0, IntPtr.Zero);
29.    }
30. }