Visual C++ and MFC Programming 2nd Edition

Chapter 16: Text-Based Controls Visual C++ and MFC Fundamentals

this reason, always make sure that you design bitmaps that have the same dimension.

Here is an example of using this method:

BOOL CDialog6Dlg::OnInitDialog()

{

CDialog::OnInitDialog();

...

// TODO: Add extra initialization here

CBitmapButton *btnMap = new CBitmapButton;

btnMap->Create(NULL, WS_CHILD|WS_VISIBLE|BS_OWNERDRAW,

CRect(10,10,100,100), this, IDC_BTN_NEW);

btnMap->LoadBitmaps(IDB_BMP_BTN1, IDB_BMP_BTN2,

IDB_BMP_BTN3, IDB_BMP_BTN4);

btnMap->SizeToContent();

return TRUE; // return TRUE unless you set the focus to a control

}

As you may realize, if you create a bitmap button strictly using this approach, it may not

work. The suggestion is to "subclass" your button class so the messages sent to the

bitmap button would be applied effectively. The function used to do this is the

CWnd::SubclassDlgItem() method and its syntax is:

BOOL SubclassDlgItem( UINT nID, CWnd* pParent );

The first argument is the resource ID of the existing button. The second argument is the

control that is hosting the button; this is usually the dialog box but it can be another

control container.

Practical Learning: Creating Bitmap Buttons

1. Continue from the Associates application.
   To add a help button, in the constructor of the CCompanyForms class, add the
   PSP_HASHELP flag as follows:

CCompanyForms::CCompanyForms()

: CPropertyPage(CCompanyForms::IDD)

{

m_psp.dwFlags |= PSP_HASHELP;

}

2. From the resources that accompany this book, import the following bitmaps and
   change their IDs as follows

File ID File ID

canceldis.bmp IDB_CANCEL_DIS cancelfoc.bmp IDB_CANCEL_FOC

cancelnrm.bmp IDB_CANCEL_NRM cancelsel.bmp IDB_CANCEL_SEL

helpdis.bmp IDB_HELP_DIS helpfoc.bmp IDB_HELP_FOC

helpnrm.bmp IDB_HELP_NRM helpsel.bmp IDB_HELP_SEL

okdef.bmp IDB_OK_DEF okdis.bmp IDB_OK_DIS

okfoc.bmp IDB_OK_FOC oksel.bmp IDB_OK_SEL

3. In the header of the CCompanySheet class, declare three CBitmapButton variables as
   follows: