Advanced MFC Programming

Chapter 9. Font
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}
{
Since this member function may be called when either BACK SPACE or DELETE key is pressed, we
need to delete the selected text in both cases. If deleting the selected text is successful, the function will
return. Otherwise it means there is no currently selected text, so we go on to delete a single character.
Message Handlers for Cut, Copy Paste Commands
In the sample, both WM_COMMAND and UPDATE_COMMAND_UI message hanlders are added for command
ID_EDIT_CUT, ID_EDIT_COPY and ID_EDIT_PASTE in class CGDIDoc. We need to enable commands Edit |
Copy and Edit | Cut if there is selected text. So functions CGDIDoc::OnUpdateEditCopy(...) and
CGDIDoc::OnUpdateEditCut(...) are implemented as follows:
void CGDIDoc::OnUpdateEditCopy(CCmdUI* pCmdUI)
{
BOOL bEnable=TRUE;
}
if(m_nSelIndexBgn == -1 || m_nSelIndexEnd == -1)bEnable=FALSE;
if(m_nSelIndexBgn == m_nSelIndexEnd)bEnable=FALSE;
pCmdUI->Enable(bEnable);
void CGDIDoc::OnUpdateEditCut(CCmdUI* pCmdUI)
{
BOOL bEnable=TRUE;
}
if(m_nSelIndexBgn == -1 || m_nSelIndexEnd == -1)bEnable=FALSE;
if(m_nSelIndexBgn == m_nSelIndexEnd)bEnable=FALSE;
pCmdUI->Enable(bEnable);
Two functions are implemented exactly the same. For function CGDIDoc::OnUpdateEditPaste(…), we
need to check if there is data available in the clipboard, if so, the command will be enabled. This checking
can be implemented by calling function ::IsClipboardFormatAvailable(…) with appropriate data format
passed to it. The function will return FALSE if there is no data present in the clipboard for the specified
data format. The following is the implementation of funcition CGDIDoc::OnUpdateEditPaste(…):
void CGDIDoc::OnUpdateEditPaste(CCmdUI* pCmdUI)
{
pCmdUI->Enable(::IsClipboardFormatAvailable(CF_TEXT));
}
Command Edit | Copy is implemented as follows:
void CGDIDoc::OnEditCopy()
{
CString szStr;
int nSel;
int nNum;
HANDLE hMem;
LPSTR lpStr;
if(m_nSelIndexEnd > m_nSelIndexBgn)
{
nSel=m_nSelIndexBgn;
nNum=m_nSelIndexEnd-m_nSelIndexBgn;
}
else
{
nSel=m_nSelIndexEnd;
nNum=m_nSelIndexBgn-m_nSelIndexEnd;
}
szStr=m_szText.Mid(nSel, nNum);
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