Advanced MFC Programming

Chapter 9. Font
}
if(m_nSelIndexBgn == -1)m_nSelIndexBgn=m_nCaretIndex;
else
{
m_nSelIndexEnd=m_nCaretIndex;
UpdateAllViews(NULL);
}
GetCGDIView()->RedrawCaret();
We want to use this function to set both m_nSelIndexBgn and m_nSelIndexEnd, so that it can be called
in response to any of the three mouse messages. If the value of m_nSelIndexBgn is -1, it means there is no
currently selected text. In this case, we need to update m_nSelIndexBgn (This is the situation that the left
button of the mouse is pressed down). In other cases (If m_nSelIndexBgn is not -1, the function must be
called in response to mouse moving or left button up event), we need to update the value of
m_nSelIndexEnd, then update the client window.
Handling Mouse Events
First function CGDIView::OnLButtonDown(…) is modified as follows:
Old Version:
void CGDIView::OnLButtonDown(UINT nFlags, CPoint point)
{
CGDIDoc *ptrDoc;
}
ptrDoc=(CGDIDoc *)GetDocument();
if(::GetCursor() == m_hCur)ptrDoc->SetCaret(point);
CScrollView::OnLButtonDown(nFlags, point);
New Version:
void CGDIView::OnLButtonDown(UINT nFlags, CPoint point)
{
CGDIDoc *ptrDoc;
}
ptrDoc=(CGDIDoc *)GetDocument();
ptrDoc->ResetSelection();
if(::GetCursor() == m_hCur)ptrDoc->SetCaret(point);
CScrollView::OnLButtonDown(nFlags, point);
The only thing added to this function is resetting the selection indices stored in the document. Other
changes are implemented in the updated function CGDIView::SetCaret(…).
Two other message handlers for WM_LBUTTONUP and WM_MOUSEMOVE are added through using Class
Wizard. The corresponding functions are CGDIView::OnLButtonUp(…) and CGDIView::OnMouseMove(…)
respectively.
Function CGDIView::OnMouseMove(…) is implemented as follows:
void CGDIView::OnMouseMove(UINT nFlags, CPoint point)
{
CGDIDoc *ptrDoc;
}
if(nFlags & MK_LBUTTON)
{
ptrDoc=(CGDIDoc *)GetDocument();
if(::GetCursor() == m_hCur)ptrDoc->SetCaret(point);
}
CScrollView::OnMouseMove(nFlags, point);
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