Re: Passing a string between dialogs

From:
"Giovanni Dicanio" <giovanni.dicanio@invalid.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Sat, 29 Mar 2008 01:01:27 +0100
Message-ID:
<ON#cfBTkIHA.4076@TK2MSFTNGP05.phx.gbl>
"Kahlua" <kahlua@right.here> ha scritto nel messaggio
news:RafHj.42$ta2.41@trndny05...

CStrings dont work for me because any byte in the string (array) can be 0h
I guess I need to be able to pass and Array of bytes (12 bytes max) to
MyDlg2
Please explain how I can do this.
The CString method below works fine unless there's a 0h in the string.

void CMyDlg::OnButton()
{
 CMyDlg dlg;
 dlg.m_string = MyData;
 if ( dlg.DoModal() == IDOK)
   MyData = dlg.m_string;
}


Continuing my previous post about std::vector<BYTE>, and putting it in the
context of above code snippet, I would make your "m_string" data field an
std::vector<BYTE> ('ByteArray', using typedef from aforementioned post), and
I would also rename it, like m_byteData (m_*string* is kind of misguiding,
IMHO... a string typically terminates with '\0'...), e.g.

 class CMyDlg
 {
  public:
   ...
     ByteArray m_byteData;
   ...
 };

Also 'MyData' should be of type 'ByteArray'.

The assignment with operator= works fine, and if your array is not big (12
bytes is fine), there are no performance problems on modern hardware.

If you have a bigger array, I would suggest you to avoid deep copies due to
operator=, and use pointers (or references) instead.
But it seems like a useless complication for your particular problem.

Moreover, I prefer embedding data fields into get/set accessor methods,
instead of exposing public data fields, e.g.

  class CMyDlg
  {
   public:
      ...

      //
      // Access ByteArray field using get/set accessors
      //

     void SetBytes( const ByteArray & source )
     {
         m_byteData = source;
     }

     const ByteArray & GetBytes() const
     {
         return m_byteData;
     }

        ...

     // ByteArray instance is private
    private:

      ByteArray m_byteData;
  };

Giovanni

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