Visual C++ and MFC Programming 2nd Edition

Visual C++ and MFC Fundamentals Chapter 18: Progress-Based Controls

Practical Learning: Using the OnTimer Event

1. To generate the OnTimer() event, in the Class View tab, click the CRandShapesDlg

class. In the Properties window, click the Messages button

2. Click the WM_TIMER field and click the arrow of its combo box. Select
   OnTimer and implement the event as follows:

void CRandShapesDlg::OnTimer(UINT nIDEvent)

{

// TODO: Add your message handler code here and/or call default

CClientDC dc(this);

int x = (rand() % DlgWidth) + 10;

int y = (rand() % DlgHeight) + 10;

CBrush BrushRand(RGB(rand() % 255, rand() % 255, rand() % 255));

CPen PenRand(PS_SOLID, 1, RGB(rand() % 255,

rand() % 255, rand() % 255));

CBrush *pOldBrush = dc.SelectObject(&BrushRand);

CPen *pOldPen = dc.SelectObject(&PenRand);

switch(rand() % 5)

{

case 0:

dc.Ellipse(x, abs(y-200), abs(y-x), y);

break;

case 1:

dc.Rectangle(y, x, abs(y-x), (x+y)%255);

break;

case 2:

dc.RoundRect(y, x, y, x, abs(x-y), x+y);

break;

case 3:

dc.Ellipse(y, x, abs(x-y), x+y);

break;

case 4:

dc.Rectangle(x, y, abs(x-y), x+y);

break;

}

dc.SelectObject(pOldBrush);

dc.SelectObject(pOldPen);

CDialog::OnTimer(nIDEvent);

}

3. To generate a random seed and to hide the cursor, in the OnInitDialog() event, call
   ShorCursor(FALSE) and srand():

BOOL CRandShapesDlg::OnInitDialog()

{

CDialog::OnInitDialog();

// Set the icon for this dialog. The framework does this automatically

// when the application's main window is not a dialog

SetIcon(m_hIcon, TRUE); // Set big icon

SetIcon(m_hIcon, FALSE); // Set small icon

// TODO: Add extra initialization here