MFC button handler to open and show an image.

open_image.cpp

// Open image
  CString FilePathName;
  CFileDialog dlg(TRUE);///TRUE为OPEN对话框，FALSE为SAVE AS对话框

  if (dlg.DoModal() == IDOK) {
    FilePathName = dlg.GetPathName();
    GetDlgItem(IMAGE_FILENAME)->SetWindowText(FilePathName);
    CT2CA pszConvertedAnsiString(FilePathName);
    cv::Mat img = cv::imread(std::string(pszConvertedAnsiString),
                             CV_LOAD_IMAGE_UNCHANGED);
    //if (!img.empty()) {
    //  cv::namedWindow("Preview",
    //                  CV_WINDOW_AUTOSIZE); //create a window with the name "Preview"
    //  cv::imshow("Preview",
    //             img); //display the image which is stored in the 'img' in the "Preview" window
    //  cv::waitKey(0); //wait infinite time for a keypress
    //  cv::destroyWindow("Preview"); //destroy the window with the name, "Preview"
    //}
  }