Question of CEdit control

edwardlau@hactl.com.hk
Wednesday, October 30, 1996

     Environment: MSVC 4.0 / Win95
     
     I am trying to write a derived CEdit class to simlulate the 
     functionality of masked edit control. After reading from the discussion 
     for the procedure for developing type over mode, I almost succeed to 
     develop a mask with literal characters inside. (E.g., date time format, 
     which is dd/mm/yy, in which the slash is the literal character). It can 
     skip pass the literal character in the OnChar function, but what I 
     still cannot succeed is when backspace or delete key is pressed - it 
     works fine for 'yy', but not 'dd' or 'mm' since the literal character 
     will move to the left as well. I know this is normal behaviour but 
     that's not what I want. What I want is when the user press backspace or 
     insert character, the literal characters still remains in its original 
     position. How can I achieve this??
     
     
     Below is part of the code extracted from OnChar of my derived class:
     
     
     
     if (b_isTypeOverMode)
     {
        WORD wPosition = LOWORD(GetSel());
               
        if (bMaskHasLiteralChar)
        {
           UINT iSpecPos;
           BOOL bPosfound = FALSE;
           CUIntArray* parint = GetLiteralCharPosArray();
     
           iSpecPos = (m_bIsBackSpaceorDelete) ? (UINT)wPosition - 1 :      
                        (UINT)wPosition;
                                                                            
           for (int idx = 0; idx < parint->GetSize(); idx++)
           {
              if (parint->GetAt(idx) == iSpecPos)
              {
                 bPosfound = TRUE;
                 break;
              }
           }
                                
           if ((bPosfound) && (!m_bIsBackSpaceorDelete))
               wPosition++;
           else if ((bPosfound) && (m_bIsBackSpaceorDelete))
               wPosition--;
        }
     
        if (m_bIsBackSpaceorDelete)
           SetSel(wPosition, wPosition--);
        else
           SetSel(wPosition, wPosition++);
                        
     }
     
     CEdit::OnChar(nChar, nRepCnt, nFlags);
                

---

David Little -- dlittle@equinoxcorp.com
Thursday, October 31, 1996

[Mini-digest: 2 responses]

I believe that whatever you are doing in the OnChar class is being =
negated by your call to CEdit::OnChar().  Since you are defining your =
own behavior, you don't need the base class, unless it is a case that =
you didn't handle.  If you decided to have a CEdit box that only =
accepted a Y or N, you could do this:

void CYorNOnly::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags)
{
	switch(nChar)
	{
	case 'Y':
	case 'N':
	  CEdit::OnChar(nChar, nRepCnt, nFlags);  // call base class for normal =
processing
	  return;
	default:
	   return;   // do nothing for any other character
	}
}

Hope this helps...

David

----------
From: 	edwardlau@hactl.com.hk[SMTP:edwardlau@hactl.com.hk]
Sent: 	Tuesday, October 29, 1996 9:30 PM
To: 	mfc-l@netcom.com
Subject: 	Question of CEdit control

     Environment: MSVC 4.0 / Win95
    =20
     I am trying to write a derived CEdit class to simlulate the=20
     functionality of masked edit control. After reading from the =
discussion=20
     for the procedure for developing type over mode, I almost succeed =
to=20
     develop a mask with literal characters inside. (E.g., date time =
format,=20
     which is dd/mm/yy, in which the slash is the literal character). It =
can=20
     skip pass the literal character in the OnChar function, but what I=20
     still cannot succeed is when backspace or delete key is pressed - =
it=20
     works fine for 'yy', but not 'dd' or 'mm' since the literal =
character=20
     will move to the left as well. I know this is normal behaviour but=20
     that's not what I want. What I want is when the user press =
backspace or=20
     insert character, the literal characters still remains in its =
original=20
     position. How can I achieve this??
    =20
    =20
     Below is part of the code extracted from OnChar of my derived =
class:
    =20
    =20
    =20
     if (b_isTypeOverMode)
     {
        WORD wPosition =3D LOWORD(GetSel());
              =20
        if (bMaskHasLiteralChar)
        {
           UINT iSpecPos;
           BOOL bPosfound =3D FALSE;
           CUIntArray* parint =3D GetLiteralCharPosArray();
    =20
           iSpecPos =3D (m_bIsBackSpaceorDelete) ? (UINT)wPosition - 1 : =
    =20
                        (UINT)wPosition;
                                                                         =
  =20
           for (int idx =3D 0; idx < parint->GetSize(); idx++)
           {
              if (parint->GetAt(idx) =3D=3D iSpecPos)
              {
                 bPosfound =3D TRUE;
                 break;
              }
           }
                               =20
           if ((bPosfound) && (!m_bIsBackSpaceorDelete))
               wPosition++;
           else if ((bPosfound) && (m_bIsBackSpaceorDelete))
               wPosition--;
        }
    =20
        if (m_bIsBackSpaceorDelete)
           SetSel(wPosition, wPosition--);
        else
           SetSel(wPosition, wPosition++);
                       =20
     }
    =20
     CEdit::OnChar(nChar, nRepCnt, nFlags);
               =20


-----From: "Jim Alsup" 

I'm not a 100% sure, but it sounds to me like you want to turn the backspace or 
delete keystoke action into a replace the current character with 
a space and possibly adjust cursor position (for backspace).  I'd probably 
attempt to adjust the edit buffer contents myself and avoid calling the
base call function "CEdit::OnChar(nChar, nRepCnt, nFlags)" for
these cases.  It should be straightforward enough.

-jim  ja@epsisupport.com

---

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