Advanced MFC Programming

Chapter 9. Font
CString szSub;
int nFwd;
}
szSub=m_szText.Right(m_szText.GetLength()-m_nCaretIndex);
nFwd=szSub.Find(' ');
if(nFwd == -1)EndCaret();
else
{
m_nCaretIndex+=nFwd+1;
GetCGDIView()->RedrawCaret();
}
void CGDIDoc::BackwardCaretToBlank()
{
CString szSub;
int nBkd;
}
szSub=m_szText.Left(m_nCaretIndex-1);
nBkd=szSub.ReverseFind(' ');
if(nBkd == -1)HomeCaret();
else
{
m_nCaretIndex-=szSub.GetLength()-nBkd;
GetCGDIView()->RedrawCaret();
}
Within the two functions, a local variable szSub is used to store the sub-string before or after the caret,
and function CString::Find(…) or CString::ReverseFind(…) is called to find the position of the nearest
blank. In case the blank is not found, we need to move the caret to the beginning or end of the text. If it is
found, we just increment or decrement m_nCaretIndex by an appropriate value.
On the view side, we need to move the caret when any of the following keys is pressed together with
CTRL: HOME, END, Left and Right ARROW. These keystroke events can be trapped by handling
WM_KEYDOWN message. To detect if the CTRL key is held down, we can call API function
::GetKeyState(…) to check the key state.
Function ::GetKeyState(…) can be used to check the current state of any key. We need to pass the
virtual key code (such as VK_CONTROL, VK_SHIFT…) to this function when making the call. The returned
value is a SHORT type integer. The high order of this value indicates if the key is held down, the lower order
indicates if the key is toggled, which is applicable to keys such as CAPS LOCK, NUM LOCK or INSERT.
Moving Caret Using Keyboard
Function CGDIView::OnKeyDown(…) is modified as follows to add the new features to the application:
void CGDIView::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
CGDIDoc *ptrDoc;
SHORT nKeyState;
ptrDoc=(CGDIDoc *)GetDocument();
ASSERT(ptrDoc);
switch(nChar)
{
case VK_LEFT:
{
nKeyState=GetKeyState(VK_CONTROL);
if(HIBYTE(nKeyState) != 0)
{
ptrDoc->BackwardCaretToBlank();
}
else ptrDoc->BackwardCaret();
break;
}
case VK_RIGHT:
{
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