mfc - How can I dynamically allocate a CFile type of variable? (C++, CFile, new) - 


static tchar based_code szfilter[] = _t("yuv files|*.yuv|") cfiledialog filedlg(true, _t("yuv"), _t("bus.yuv"), ofn_filemustexist | ofn_hidereadonly, szfilter); if (filedlg.domodal() == idok) {     cstring pathname = filedlg.getpathname();     cfile* pimgfile = null;     pimgfile = new cfile(pathname, cfile::moderead || cfile::typebinary); }

i refer example in following site. https://msdn.microsoft.com/en-us/library/b569d0t4.aspx

static tchar based_code szfilter[] = _t("yuv files|*.yuv|") cfiledialog filedlg(true, _t("yuv"), _t("bus.yuv"), ofn_filemustexist | ofn_hidereadonly, szfilter); if (filedlg.domodal() == idok) {     cstring pathname = filedlg.getpathname();     cfile imgfile;     cfileexception e;     if (!imgfile.open(pathname, cfile::moderead || cfile::typebinary, &e))     {         trace(_t("file not opened %d\n"), e.m_cause);     } }

i refer first example in following site. https://msdn.microsoft.com/en-us/library/hwbccf8z.aspx

i used method of cfile, open, in second code.

for upper code, how can open file?

when use dynamic allocation, automatically open file?

imglength = pimgfile->getlength(); cstring str; str.format(_t("your system.ini file %i64u bytes long."), imglength); afxmessagebox(str);

i tried append code first code.

it works without problems, , think variable, pimgfile, points address of file well.

in general there no need create cfile on heap. there several constructors of cfile:

cfile( ); cfile(    catltransactionmanager* ptm ); cfile(    handle hfile  ); cfile(    lpctstr lpszfilename,    uint nopenflags  ); cfile(    lpctstr lpszfilename,    uint nopenflags,    catltransactionmanager* ptm );

the fourth , fifth constructors call open internally. open file.

the other problem should use operator | not || combine open flags.

i'd suggest using default cfile constructor , call open then. please note optionally can pass cfileexception open call. in case wont throw exception in case of error , wont need place try/catch around it. so, basically, have got more options control behavior if call open manually.


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