MemoryStream并构造一个字节数组

Question

I am using a MemoryStream to construct an array of bytes i need to send to a server.I have thre questions:

1) Is there a better way to construct an array of bytes than this ?

2) Why this pice of code writes bogus in my memory stream ?

var
  serial : word;
  MS : TMemoryStream;
const
  somebytes : array [0..1] of byte = ($72,$72);
...
begin
      MS := TMemoryStream.Create();
      try
      MS.Write(somebytes[0],2);
      serial := $3E6C;
      MS.Write(serial,2);
      finally
      MS.Free;
end;

Using the debugger i see that in the stream is added the value $6F32 instead of $3E6C.

3) If i call

MS.Position := 2;

and then i access PByte(MS.Memory)^ why do i get the first byte in the stream instead of the third?

Answer 1

Is there a better way to construct an array of bytes than this?

That's a perfectly reasonable way to do it, in my view.

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I see that in the stream is added the value $6F32 instead of $3E6C.

Check again. The correct values are in fact added. But beware of the traps of little endian data types. The 4 bytes added to your stream, in order, are: $72, $72, $6C, $3E.

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Why do I get the first byte in the stream instead of the third?

Because the Memory property always refers to the beginning of the stream. It does not take account of the stream's current position.