FIX: SetMinHeight Does Not Work Correctly with CStatusBar

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View products that this article applies to.

This article was previously published under Q151031

SYMPTOMS

Using the SetMinHeight function to change the height of a CStatusBar object has no effect.

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The CStatusBar class maintains the height of the status window control in a member variable named m_nMinHeight. The m_nMinHeight variable is not updated correctly when the SetMinHeight function is used to change the height of the status bar.

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RESOLUTION

You can work around this problem by setting m_nMinHeight to the correct value in response to SetMinHeight. This is accomplished by deriving a class from CStatusBar and handling the SB_SETMINHEIGHT message. In this handler, call Default(), and then set m_nMinHeight to the new height.

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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 Visual C++ version 6.0.

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MORE INFORMATION

The sample code below illustrates how to work around the problem. Use the CMyStatusBar class instead of CStatusBar if you want to change the height of the status bar using SetMinHeight function. Be sure to call RecalcLayout on the parent of the status bar to see this change in height immediately.

NOTE: The workaround uses the undocumented m_nMinHeight member variable of CStatusBar. Hence the code in the workaround may not be compatible with future versions of MFC.

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Sample Code

   // MyStatusBar.h : header file
   // 

   //////////////////////////////////////////////////////////////////// 
   // CMyStatusBar window

   #ifndef __MYSTATUSBAR_H__
   #define __MYSTATUSBAR_H__

   class CMyStatusBar : public CStatusBar
   {
   // Construction
   public:
        CMyStatusBar() {}

   // Implementation
   public:
        virtual ~CMyStatusBar() {}

        // Generated message map functions
   protected:
        //{{AFX_MSG(CMyStatusBar)
        //NOTE-the ClassWizard will add and remove member functions here.
        //}}AFX_MSG

   #if _MFC_VER == 0x0400 || _MFC_VER == 0x0410 || _MFC_VER == 0x420 ||\ 
   _MFC_VER == 0x421

         afx_msg LRESULT OnSetMinHeight(WPARAM wParam, LPARAM);
   #endif

        DECLARE_MESSAGE_MAP()
   };

   #endif //__MYSTATUSBAR_H__

   //////////////////////////////////////////////////////////////////// 

   // MyStatusBar.cpp : implementation file
   // 

   #include "stdafx.h"
   #include "MyStatusBar.h"

   #ifdef _DEBUG
   #define new DEBUG_NEW
   #undef THIS_FILE
   static char THIS_FILE[] = __FILE__;
   #endif

   //////////////////////////////////////////////////////////////////// 
   // CMyStatusBar

   BEGIN_MESSAGE_MAP(CMyStatusBar, CStatusBar)
        //{{AFX_MSG_MAP(CMyStatusBar)
        //NOTE-the ClassWizard will add and remove mapping macros here.
        //}}AFX_MSG_MAP

   #if _MFC_VER == 0x0400 || _MFC_VER == 0x0410 || _MFC_VER == 0x420 ||\ 
   _MFC_VER == 0x421

        ON_MESSAGE(SB_SETMINHEIGHT, OnSetMinHeight)
   #endif

   END_MESSAGE_MAP()

   ///////////////////////////////////////////////////////////////////// 
   // CMyStatusBar message handlers

   #if _MFC_VER == 0x0400 || _MFC_VER == 0x0410 || _MFC_VER == 0x420 ||\ 
   _MFC_VER == 0x421

   LRESULT CMyStatusBar::OnSetMinHeight(WPARAM wParam, LPARAM)
   {
        LRESULT lResult = Default();
        m_nMinHeight = wParam;
        return lResult;
   }
   #endif

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REFERENCES

For more information, please see: Visual C++ Books Online, and the Win32 SDK documentation.

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APPLIES TO

Microsoft Foundation Class Library 4.2, when used with:

Microsoft Visual C++ 4.2 Enterprise Edition
Microsoft Visual C++ 5.0 Enterprise Edition
Microsoft Visual C++ 4.0 Professional Edition
Microsoft Visual C++ 4.1 Subscription
Microsoft Visual C++ 4.2 Professional Edition
Microsoft Visual C++ 5.0 Professional Edition
Microsoft Visual C++ 5.0 Learning Edition
Microsoft Visual C++ 5.0 Learning Edition

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kbbug kbfix kbnoupdate kbstatbar kbui kbuidesign kbvc600fix KB151031

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Retired KB Content Disclaimer

This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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