Bitmap in Buttons disappear - mfc

Question

I have a CFormView SDI which calls and opens up a CDialog.
In the CDialog I have a button which has a bitmap displayed.
All works well, until I close the CDialog.
When I open up the same CDialog (using create function), the button appears, and the button's functionality is there, however the bitmap disappears.
Can someone please tell me why the bitmap on the button disappears on subsequent calls to CDialog?
Thank you in advance.
Here is the code:
In the CFormView I have a button that creates the CDialog:
void CTest4View::OnButton1()
{
m_dialog_calculator.Create(IDD_DIALOG1, GetDesktopWindow());
m_dialog_calculator.ShowWindow(SW_SHOW);
}
In the CDialog I have the bitmap put on the button in the InitDialog:
BOOL CCalculator::OnInitDialog()
{
CDialog::OnInitDialog();
if(!bitmapNew.LoadBitmap(IDB_BITMAP_NEW)){
MessageBox("problem in loadbitmap");
}
if(!m_button.SetBitmap(bitmapNew)){
MessageBox("problem in SetBitmap");
}
bitmapOpen.LoadBitmap(IDB_BITMAP_OPEN);
m_buttonOpen.SetBitmap(bitmapOpen);
//==========================
return TRUE; // return TRUE unless you set the focus to a control
// EXCEPTION: OCX Property Pages should return FALSE
}
Upon further investigation, the problem seems to be in: m_button.SetBitmap(bitmapNew) since this returns FALSE. Can someone please help me?

Answer 1

Quick fix:
void CTest4View::OnButton1()
{
// only create the dialog once
if (m_dialog_calculator.m_hWnd==NULL)
m_dialog_calculator.Create(IDD_DIALOG1, GetDesktopWindow());
m_dialog_calculator.ShowWindow(SW_SHOW);
}
Additional information 1:
The information that OP provided in his question/code is quite little, so I actually have to recreate a similar test project to guess what is wrong with the missing bitmap. What I found is that the CDialog and CBitmap is being created multiple times when the button is pressed, this causes subsequent creation api call to fail, other than the first creation call. The result is some unexpected behavior as you can see now.
The program is supposed to generate some assertion errors when run in debug mode due to the creation failure but I guess the OP compiled it in release mode so all warnings are being suppressed.
The problem occurred because the calculator dialog is created as a modeless dialog as compared to a normal DoModal way of activation. The usual way of doing such modeless dialog is to create the dialog only once, by monitoring the m_hWnd member variable. When the user want the dialog to be dismissed, it is simply being hidden instead of being destroyed. This will avoid all the multiple creation problems altogether.
I guess presently, the calculator dialog is assumed to be closed and destroy by clicking the "X" button on the top right of dialog, well, actually it is only hidden but not actually being destroyed by the default handling of CDialog. The correct way to dismiss the modeless calculator dialog is thus to overide the OnClose event to hide it using ShowWindow(SW_HIDE). To activate it again, use ShowWindow(SW_SHOWNORMAL).