Advanced MFC Programming

Chapter 5. Common Controls
"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"
};
NM_UPDOWN *pNMUpDown=(NM_UPDOWN*)pNMHDR;
}
nNewPos=pNMUpDown->iPos+pNMUpDown->iDelta;
if(nNewPos >= 0 && nNewPos SetWindowText(szNumber[nNewPos]);
}
*pResult=0;
The buddy’s text is set by calling function CWnd::SetWindowText(…). Here variable szNumber is a twodimensional
character array which stores strings “Zero”, “One”, “Two”…”Nine”. First we calculate the
current position of the spin control and store the result in an integer type variable nNewPos. Then we use it
as an index to table szNumber, find the appropriate string, and use it to set the text of the edit control.
In dialog box’s initialization stage, we need to set the range and position of the spin control. Since the
edit box will display nothing by default, we also need to set its initial text:
……
BOOL CCCtlDlg::OnInitDialog()
{
CDialog::OnInitDialog();
((CSpinButtonCtrl *)GetDlgItem(IDC_SPIN_STR))->SetRange(0, 9);
((CSpinButtonCtrl *)GetDlgItem(IDC_SPIN_STR))->SetPos(0);
GetDlgItem(IDC_EDIT_STR)->SetWindowText("Zero");
}
return TRUE;
With the above implementation, the spin’s buddy control will display text instead of numbers.
5.4 Bitmap Button Buddy
String text is not the only appearance a buddy control can have. We can also implement a buddy that
displays bitmaps. Because bitmap button can be easily implemented to display images, we can use it to
implement spin’s buddy control rather than using edit box.
Sample 5.4\CCtl demonstrates how to implement bitmap button buddy. It is based on sample 5.3\CCtl,
with a new spin control IDC_SPIN_BMP and a new bitmap button IDC_BUTTON_BMP added to the application.
The procedure of creating a bitmap button buddy is almost the same with creating an edit box buddy.
The only difference here is that instead of creating an edit box resource, we need to add a button resource,
and set its “Owner draw” style.
In the sample, four bitmaps are prepared to implement the bitmap button. All of them have integer
resource IDs, which are listed as follows: IDB_BITMAP_SMILE_1, IDB_BITMAP_SMILE_2,
IDB_BITMAP_SMILE_3, IDB_BITMAP_SMILE_4.
A CBitmapButton type variable is declared in class CCCtlDlg. In the dialog box’s initialization stage,
functions CWnd::SubclassDlgItem(…), CBitmapButton::LoadBitmaps(…) and CBitmapButton::
SizeToContent() are called to initialize the bitmap button. Also, the range of the spin control is set from 0
to 3, and its initial position is set to 0:
……
BOOL CCCtlDlg::OnInitDialog()
{
CDialog::OnInitDialog();
m_bmpBtn.SubclassDlgItem(IDC_BUTTON_BMP, this);
m_bmpBtn.LoadBitmaps(IDB_BITMAP_SMILE_1);
m_bmpBtn.SizeToContent();
((CSpinButtonCtrl *)GetDlgItem(IDC_SPIN_BMP))->SetRange(0, 3);
((CSpinButtonCtrl *)GetDlgItem(IDC_SPIN_BMP))->SetPos(0);
return TRUE;
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