vc初学7-修改文件对话框

void CFileApp::OpenFile()
{
 char szFilter[]="All Files (*.*)\0*.*\0Text Files(*.txt)\0*.txt\0\0";  //注意
 CString msg="File to open:";
 CFileDialog dlg(true);                                                                    //显示对话框
 dlg.m_ofn.lpstrFilter=(LPSTR)szFilter;
 if(dlg.DoModal()==IDOK)
 {
  msg+=dlg.GetFileName();
  AfxMessageBox(msg);
 }
}