byte[] ba=new byte[] {1,2,3};
byte[] bb=new byte[] {4,5,6,7,8,9};
byte[] bc;
//方法1:用MEMORYSTREAM
System.IO.MemoryStream stream=new System.IO.MemoryStream();
stream.Write(ba, 0, ba.Length );
stream.Write(bb, 0, bb.Length );
stream.Close();
bc=stream.GetBuffer();
//方法2:复制
bc=new byte[ba.Length +bb.Length ];
ba.CopyTo(bc, 0);
bb.CopyTo(bc, ba.Length);