how to append two or more wav files,plzz help

Not sure how to append them.  But you can play them in sequence in C#.

I got this code from public joe's.  It can also be found on this site.  Basically you use pinvoke to call
into the multimedia dll and play the sound

 // PlaySound()
    [DllImport( "winmm.dll", SetLastError = true,
                CallingConvention = CallingConvention.Winapi)]

    static extern bool PlaySound( string pszSound,
                                  IntPtr hMod,
                                  SoundFlags sf );

    // Flags for playing sounds.  For this example, we are reading
    // the sound from a filename, so we need only specify
    // SND_FILENAME | SND_ASYNC
    [Flags]
    public enum SoundFlags : int
    {
      SND_SYNC = 0x0000,         // play synchronously (default)
      SND_ASYNC = 0x0001,        // play asynchronously
      SND_NODEFAULT = 0x0002,    // silence (!default) if sound not found
      SND_MEMORY = 0x0004,       // pszSound points to a memory file
      SND_LOOP = 0x0008,         // loop the sound until next sndPlaySound
      SND_NOSTOP = 0x0010,       // don't stop any currently playing sound
      SND_NOWAIT = 0x00002000,   // don't wait if the driver is busy
      SND_ALIAS = 0x00010000,    // name is a registry alias
      SND_ALIAS_ID = 0x00110000, // alias is a predefined ID
      SND_FILENAME = 0x00020000, // name is file name
      SND_RESOURCE = 0x00040004  // name is resource name or atom
    }

 void PlayIt()
 {
   PlaySound( "mywavefile.wav", 0 , 0);
 }

To combine the file check out http://ccrma.stanford.edu/courses/422/projects/WaveFormat/

Use a BinaryReader and Writer to read and write the bytes into a byte array, and also manipulate
the byte header information and data chunks.

Also check out http://www.borg.com/~jglatt/tech/wave.htm
and http://www.sonicspot.com/guide/wavefiles.html

-Mike G