Mouse - worked example

key : purple - original code / blue - new code

Step 1 :

Create a new project called Mouse using the MFC AppWizard(exe). Select Single Document Application at Step 1 of the Wizard.

Step 2 :

In the CMouseView, header file declare the following :

class CMouseView : public CView
{

private:
CRect m_rectEllipse;
int m_nColor;
protected: // create from serialization only
CMouseView();
DECLARE_DYNCREATE(CMouseView)

Step 3 :

Use the Class Wizard to insert the OnLButtonDown() funtion (press "CTRL+W" to call the Class Wizard). In the CMouseView class / ID add a function to the WM_LBUTTONDOWN message. Click the add code button to progress to the next step.

Step 4 :

In the view class CMouseView, within the OnLButtonDown() function, insert the following code :

void CMouseView::OnLButtonDown(UINT nFlags, CPoint point)
{

if (m_rectEllipse.PtInRect(point)) {
if (m_nColor == GRAY_BRUSH) {

m_nColor = WHITE_BRUSH;

}
else {

m_nColor = GRAY_BRUSH;

}

InvalidateRect(m_rectEllipse);
}

}

Step 5 :

In the view class CMouseView, within the constructor, insert the following code :

CMouseView::CMouseView() : m_rectEllipse(0, 0, 200, 200)
{

m_nColor = GRAY_BRUSH;

}

Step 6 :

In the view class CMouseView, within the OnDraw() function, insert the following code :

void CMouseView::OnDraw(CDC* pDC)
{

pDC->SelectStockObject(m_nColor);
pDC->Ellipse(m_rectEllipse);

}

Click here for the basic exercise

Click here for the source code

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