Advanced MFC Programming

Chapter 7. Common Dialog Boxes
……
}
}
m_pColorDlg=NULL;
We need to destroy the windows by ourselves if the user exits the application without first closing the
color dialog box. We can override a member function OnCloseDocument(), which will be called when the
document is about to be closed. This function can be easily added through using the Class Wizard. The
following shows how it is implemented in the sample:
void CCDBDoc::OnCloseDocument()
{
if(m_pColorDlg != NULL)
{
if(m_pColorDlg->m_hWnd != NULL)m_pColorDlg->Detach();
delete m_pColorDlg;
}
if(m_pColorDmDlg != NULL)delete m_pColorDmDlg;
m_pColorDmDlg=NULL;
m_pColorDlg=NULL;
}
CDocument::OnCloseDocument();
Again, function CWnd::Detach() is called before the buffers are released.
Applying Selected Color Instantly
To make the sample more practical, another feature is added to it: when the user picks up a color, the
client window of the application will be painted with that color instantly. To implement this, a new
COLORREF type variable m_colorCur is added to class CDBDoc, which will be used to store the current color
of the client window:
……
……
class CCDBDoc : public CDocument
{
protected:
}
COLORREF m_colorCur;
The color is initialized in the constructor as follows:
……
CCDBDoc::CCDBDoc()
{
}
m_colorCur=RGB(0, 255, 255);
Member function CCDBDoc::SetCurrentColor(…) and CCDBDoc::GetCurrentColor() are added to let
us access variable m_colorCur outside the document:
……
……
class CCDBDoc : public CDocument
{
public:
void SetCurrentColor(COLORREF);
COLORREF GetCurrentColor(){return m_colorCur;}
}
Function CCDBDoc::GetCurrentColor(…) is implemented as an inline function, and function
CCDBDoc::SetCurrentColor(…) is implemented as follows:
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