private void pbStep2_Click(object sender, EventArgs e) { OpenFileDialog openFileDialog1 = new OpenFileDialog(); Config cfg = new Config(); String path = cfg.Get(Config.ANSWER_SHEET_IMG_PATH, ""); if (path != "") { openFileDialog1.InitialDirectory = path; } openFileDialog1.Title = "Chọn danh sách ảnh bài thi"; openFileDialog1.CheckFileExists = true; openFileDialog1.CheckPathExists = true; openFileDialog1.Filter = "dat Files (*.dat)|*.dat"; openFileDialog1.DefaultExt = "dat"; openFileDialog1.FilterIndex = 2; openFileDialog1.RestoreDirectory = true; openFileDialog1.ReadOnlyChecked = true; openFileDialog1.ShowReadOnly = true; if (openFileDialog1.ShowDialog() == DialogResult.OK) { string filePath = openFileDialog1.FileName; byte[] imageBytes = File.ReadAllBytes(filePath); if (SigningHelper.VerifyImages(imageBytes)) { List <Bitmap> imgs = SigningHelper.GetImagesFromEncryptedBytes(imageBytes); bgImageProcessing.RunWorkerAsync(imgs); processProgressBar.Visible = true; lbProcessProgressDescription.Visible = true; } else { MessageBox.Show("File ảnh bài thi bị lỗi!!"); } } }