Re: Handling Cut (CTRL-C) in a CListCtrl dervied control

From:
Oliver Regenfelder <oliver.regenfelder@gmx.at>
Newsgroups:
microsoft.public.vc.mfc
Date:
Sat, 22 May 2010 13:01:54 +0200
Message-ID:
<d915e$4bf7b9ab$5477403e$9566@news.inode.at>
Joseph M. Newcomer wrote:

Probably unnecessary. I have no idea what you mean by "portable" because a Windows app
can only run on Windows and Windows-like clones (e.g. WINE) so there is no portability
issue. Whenever you suggest the work "portable" you imply that the application will run
on a non-Windows platform, and this is not going to happen.


I think portable was a bad word to use. Will CTRL-C==03 hold on any version of windows
and with any locale character set?

As a first line of defense I have to say I copied that code from the MSDN almost
verbatim (for the Clippoard data bards).

ItemData *item_data = reinterpret_cast<ItemData*>(GetItemData(index));

****
What is in the ItemData field? You have not said.

ItemData is a struct holding the data of each row.
struct ItemData {
  ...
  CString epc;
  ...
};

****

HANDLE hMem = ::GlobalAlloc(0

****
Why 0? For clipboard data, it is supposed to be GMEM_MOVEABLE!


Because MSDN hat it this way? Ok. I will change it. Are there any better
sources than MSDN on using the clipboard correctly?

****

     , (item_data->epc.GetLength() + 1)* sizeof(TCHAR));
****
WHy is the comma for the first parameter the first character of the second line?


In my opinion it is more readable, but that is a personal matter of coding style
I would say.

****

if(hMem == NULL) {
    ::CloseClipboard();
    return;
}

LPVOID lptstrCopy = ::GlobalLock(hMem);

****
If it is an LPVOID, why did you call it an lptstrCopy? Nonsense. Don't use Hungarian
Notation if you can't use it correctly! This is an incorrect usage. Just drop it
entirely, it is confusing and in this case misleading.


I copied it from the MSDN, and when it didn't compile (surprise) I only changed the
type to correct it. I wil remove the hungarian notation.

****

::memcpy(lptstrCopy, item_data->epc, (item_data->epc.GetLength() + 1) *
sizeof(TCHAR));
::GlobalUnlock(hMem);

::SetClipboardData(CF_TEXT, hMem);

****
As long as item_data->epc is a TCHAR array or CString, this will be correct. Otherwise, I
have no idea what you just put into the clipboard.


Sorry yes. item_data->epc is a CString.

Where did you call ::EmptyClipboard?


I can not. I use
::OpenClipboard(NULL)
in that case the task itself holds the clipboard and you are not supposed to call
::EmptyClipboard(). This is a bad idea?

CF_TEXT will store the data in the format used by your app, and read about text
conversions on GetClipboardData.


So if I compile it as MBCS application it will automatically behave correctly and
if I later change it to be UNICODE then it will also automatically behave correctly.

Thanks,

Oliver

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