Same code worked fine for me am also using vs2008

CString str; str.Format(_T("All Files (*.dat)|*.dat||"));// change name .dat to any extension you want CFileDialog file_dlg(TRUE,NULL,NULL,OFN_OVERWRITEPROMPT,str); INT_PTR iRet = file_dlg.DoModal(); :)

M not sure this is your requirement or not add this in onpaint this->ShowWindow(SW_HIDE); this will hide the entire dialog

int main() { int a[] = {1,2,3,4,5}; printf("%d",sizeof(a)/sizeof(int)); getch(); }