using System.Runtime.InteropServices;

// winmm.dllのロード
[DllImport("winmm.dll")]
public static extern long PlaySound(String lpszName, IntPtr hModule, Int32 dwFlags);

// Flags for audio
private const int SND_SYNC   = 0x0;
private const int SND_ASYNC  = 0x1;
private const int SND_MEMORY = 0x4;
private const int SND_LOOP   = 0x8;
private const int SND_NOSTOP = 0x10;
private const int SND_NOWAIT = 0x2000;

// 再生
PlaySound("C:\Windows\Media\tada.wav",  (IntPtr)0, SND_ASYNC);