FIX: ResizeParentToFit Won't Work w/ CScrollView on Windows 95 (135118)
The information in this article applies to:
- The Microsoft Foundation Classes (MFC), when used with:
- Microsoft Visual C++, 32-bit Editions 2.2
This article was previously published under Q135118 SYMPTOMS
A CScrollView that uses ResizeParentToFit to force its parent to resize
itself such that the client area is the same size as the CScrollView
doesn't work properly. The parent frame window will be very nearly the
correct size, but it will still have vertical and horizontal scroll bars.
CFormView, which is derived from CScrollView, will have the same problem.
CAUSE
The bug is in the ResizeParentToFit function. The ResizeParentToFit
function does not properly account for cases where the child window is not
located at location (0,0).
The version of Visual C++ listed at the top of this article has been
modified. MFC was changed so that a CFormView will have the properly
sunken-edge (or 3D) look that a client window should have under Windows 95.
This change was done by adding the WS_EX_CLIENTEDGE style to all CFormView
objects when they are created. Because of this change the client area of
the CFormView is no longer at position (0,0), so ResizeParentToFit fails to
work correctly.
RESOLUTION
Override the ResizeParentToFit function, and modify it to do the proper
calculations for your CFormView-derived class. The code for
ResizeParentToFit can be found in the \MSVC20\MFC\SRC directory in the
Viewscrl.cpp file. Implement this code in your application by first
declaring it in your class, as in this example:
protected:
void ResizeParentToFit(BOOL bShrinkOnly = TRUE);
Implement the ResizeParentToFit function. To do this, copy the existing
implementation from Viewscrl.cpp, and then make the following changes in
your implementation: - Change the assert that uses MM_NONE to use 0. MM_NONE is a special
mapping mode defined for the CScrollView class. It is defined in
Viewscrl.cpp as 0; therefore, it will not be available for your derived
class.
Change this:
ASSERT( m_nMapMode != MM_NONE);
To this:
ASSERT( m_nMapMode != 0);
- Account for the offset of the client area.
Change this:
...
CalcWindowRect(rectView, CWnd::adjustOutside);
if (bShrinkOnly)
...
To this:
...
CalcWindowRect(rectView, CWnd::adjustOutside);
rectView.OffsetRect(-rectView.left, -rectView.top);
ASSERT(rectView.left == 0 && rectView.top == 0);
if (bShrinkOnly)
...
STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed
at the beginning of this article. This problem was corrected in the version
of MFC that ships with Microsoft Visual C++, 32-bit Edition, version 4.0.
| Modification Type: | Major | Last Reviewed: | 10/24/2003 |
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| Keywords: | kbBug kbfix kbNoUpdate KbUIDesign kbVC400fix KB135118 |
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