Re: Prevent invalid chars in editbox

From:

"AliR $VC++ MVP$" <AliR@online.nospam>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 19 Jul 2007 19:50:42 GMT

Message-ID:

<mgPni.22656$RX.17902@newssvr11.news.prodigy.net>

You might have better luck if you handle the WM_CHAR message

void CNumericEdit::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags)
{

   if (isprint(nChar) && !(isdigit(nChar) || nChar == '-'))
   {
      return;
   }

   CEdit::OnChar(nChar, nRepCnt, nFlags);
}

Here is one step further (only let the user enter the - sign in the
begining)
void CNumericEdit::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags)
{

   if (isprint(nChar) && !(isdigit(nChar) || nChar == '-'))
   {
      return;
   }

   if (nChar == '-')
   {
      int Start;
      int End;
      GetSel(Start,End);
      if (Start != 0)
      {
         SetSel(0,0);
      }
   }

   CEdit::OnChar(nChar, nRepCnt, nFlags);
}

Next step would be to toggle it on and off (instead of multiple - ).

AliR.

"Eric Lilja" <mindcoolerremoveme@gmail.com> wrote in message
news:ONG95sjyHHA.5408@TK2MSFTNGP02.phx.gbl...

Hello, I have an editbox in a dialog where the user is only allowed to
enter integers. However, I cannot simply set the number flag in the
resource editor because the user must be able to enter negative integers
too. Therefore, I didn't create it with that flag. Instead I subclassed
CEdit and redefined OnKeyDown():

void
NumberEditBox::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
   static const std::string valid_chars = "0123456789-";

   if (valid_chars.find(nChar) != std::string::npos)
   {
      TRACE1("%c is a valid char\n", (char)nChar);
      CEdit::OnKeyDown(nChar, nRepCnt, nFlags);
   }
}

This is basically the only code in my NumberEditBox class, no other member
functions have been introduced or redefined by me.

When the program is run, I only see traces of the valid chars, however the
invalid ones still appear in the editbox itself. What else do I need to
do? I was suprised that not letting the CEdit do anything for the unwanted
chars was not enough.

I'm using MSVC++ 8.0 SP1 on WinXP Pro SP2.

- Eric

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