CCheckListbox and item height

Well, MFC shows its age.

Although many fairly new programmers, who started to write code after the year 2000, think MFC is old, but in 90’s it was not.
It’s not as elegant as Cocoa or even new .NET ( with C#. .NET for C++ looks like too much overloaded truck with redundant stuffs on it. ).
However, it solves problems for its generation, and there was good reason for MS people to take such design.

However, they had to renovate it. There are many issues like control vs. view for similar components, inconsistent way to deal with widgets, etc.
Today I found a problem with item height for CCheckListBox. With VS resource editor, you can change “font size” of a dialog box or a window. What it actually does is not to change font size for widgets on them.

font size( I think it’s also a problem. What it actually does is to change “scale” of the coordinate system on that dialog box or window. Because the scale is changed, everything like button size is also changed as well as font size. So, it’s not right to name the property “Font(Size)”. )

Problem is that when an instance of CCheckListbox is instantiated and items are added to that, it checks whether each item height is bigger than its minimum size like this. ( Please focus on the last line. )

void CCheckListBox::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
  // You must override DrawItem and MeasureItem for LBS_OWNERDRAWVARIABLE

  CDC* pDC = CDC::FromHandle(lpDrawItemStruct->hDC);

  if (((LONG)(lpDrawItemStruct->itemID) >= 0) &&
    (lpDrawItemStruct->itemAction & (ODA_DRAWENTIRE | ODA_SELECT)))
    int cyItem = GetItemHeight(lpDrawItemStruct->itemID);
    BOOL fDisabled = !IsWindowEnabled() || !IsEnabled(lpDrawItemStruct->itemID);

    COLORREF newTextColor = fDisabled ?
      RGB(0x80, 0x80, 0x80) : GetSysColor(COLOR_WINDOWTEXT);  // light gray
    COLORREF oldTextColor = pDC->SetTextColor(newTextColor);

    COLORREF newBkColor = GetSysColor(COLOR_WINDOW);
    COLORREF oldBkColor = pDC->SetBkColor(newBkColor);

    if (newTextColor == newBkColor)
      newTextColor = RGB(0xC0, 0xC0, 0xC0);   // dark gray

    if (!fDisabled && ((lpDrawItemStruct->itemState & ODS_SELECTED) != 0))

    if (m_cyText == 0)
      VERIFY(cyItem >= CalcMinimumItemHeight());

It turned out that cyItem, which is height of an interested item at that moment, is less than the minimum height if the font size is set to 12.
So, MFC is not updated to work with its visual resource editor or vice versa.
At least there should be some property to choose item height based on chosen “Font size” on the visual editor. If the code for MFC presents relevant error message when debugging, it can be even better.

Anyway, if you set the item height using SetItemHeight() sufficiently, its debugger will not complain again. This is not documented in the section for CCheckListBox at all.

We complain that Apple let Mac OS X and its Cocoa framework behind due to its focus on iOS. ( kernel is the same on the both and Cocoa is almost same to CocoaTouch, but still.. ) However, Apple people keep updating their tool set to work properly with their framework. MS doesn’t seem to be considerate on this long-lived-but-dependable MFC framework. Yes, model-wise, .NET is better. But I often notice that .NET with C++ is too bloated and .NET with C# is too weak. For native environment, MS doesn’t have new framework to replace MFC for C++.
Nowadays, it doesn’t seem to me that there are many S/W engineers working with MFC/C++. So, probably they don’t ask much to MS. Well, in the world of Web app, Java and C#, where people usually justify “computers are getting faster. So, bytecode/VM language like C#/Java are OK.”. I think it’s understandable argument. But still it’s not sufficient to me. It’s like to use 486 computers with the speed of 386 computers. For convenience of using and learning a language, MS gave up many things in C#/.NET, which can be done more easily with C++/MFC/Win32.

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: