How do I concatenate 2 bytes?

Question

I have 2 bytes:

byte b1 = 0x5a;  
byte b2 = 0x25;

How do I get 0x5a25 ?

Answer 1

A more explicit solution (also one that might be easier to understand and extend to byte to int i.e.):

using System.Runtime.InteropServices;
[StructLayout(LayoutKind.Explicit)]
struct Byte2Short {
  [FieldOffset(0)]
  public byte lowerByte;
  [FieldOffset(1)]
  public byte higherByte;
  [FieldOffset(0)]
  public short Short;
}

Usage:

var result = (new Byte2Short(){lowerByte = b1, higherByte = b2}).Short;

This lets the compiler do all the bit-fiddling and since Byte2Short is a struct, not a class, the new does not even allocate a new heap object ;)