private void btnFind_Click(object sender, RoutedEventArgs e)
 {
     var record = db.GetAll();
     if(cbxType.SelectedIndex == 1)
     {
         if(string.IsNullOrEmpty(txtKey.Text))
         {
             MessageBox.Show("Vui lòng nhập mã độc giả");
             return;
         }
         record = record.Where(r => r.MaDocGia == int.Parse(txtKey.Text)).ToList();
     }
     if(cbxType.SelectedIndex == 2)
     {
         if (string.IsNullOrEmpty(txtKey.Text))
         {
             MessageBox.Show("Vui lòng nhập tên độc giả");
             return;
         }
         record = record.Where(r => r.TenDocGia.Contains(txtKey.Text)).ToList();
     }
     if(chkHetHan.IsChecked.Value)
     {
         var now = DateTime.Now;
         record = record.Where(r => r.NgayHetHan < now).ToList();
     }
     if(chkVienChuc.IsChecked.Value)
     {
         record = record.Where(r => r.VienChuc.Value == true).ToList();
     }
     if (record.Count > 0)
     {
         List<TKDocGia> value = new List<TKDocGia>();
         foreach(var row in record)
         {
             var item = new TKDocGia(row);
             item.DangMuon = DangMuonCout(row);
             value.Add(item);
         }
         docGiaDataGrid.ItemsSource = value;
     }
     else MessageBox.Show("Không tìm thấy độc giả");
 }
 private bool WriteExcel()
 {
     try
     {
         COMExcel.Application exApp = new COMExcel.Application();
         string workbookPath = System.IO.Path.Combine(System.IO.Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), @"Resource\BCDocGia.xlsx");
         COMExcel.Workbook exBook = exApp.Workbooks.Open(workbookPath,
                 0, false, 5, "", "", false, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "",
                 true, false, 0, true, false, false);
         COMExcel.Worksheet exSheet = (COMExcel.Worksheet)exBook.Worksheets[1];
         ((Microsoft.Office.Interop.Excel._Worksheet)exSheet).Activate();
         // Xuất danh sách
         int i = 1;
         TKDocGia record = new TKDocGia();
         foreach(var item in docGiaDataGrid.Items)
         {
             record = (TKDocGia)item;
             exSheet.Cells[3 + i, 1] = i;
             exSheet.Cells[3 + i, 2] = record.MaDocGia;
             exSheet.Cells[3 + i, 3] = record.TenDocGia;
             exSheet.Cells[3 + i, 4] = "'" + record.SDT;
             exSheet.Cells[3 + i, 5] = record.Email;
             exSheet.Cells[3 + i, 6] = record.NgayCap.Value.ToShortDateString();
             exSheet.Cells[3 + i, 7] = record.NgayHetHan.Value.ToShortDateString();
             exSheet.Cells[3 + i, 8] = record.NamTotNgiep;
             if (record.VienChuc.Value)
                 exSheet.Cells[3 + i, 9] = "x";
             exSheet.Cells[3 + i, 10] = record.DiaChi;
             exSheet.Cells[3 + i, 11] = record.DangMuon;
             i++;
         }
         i = i + 2;
         COMExcel.Range r = (COMExcel.Range)exSheet.get_Range("A4", "K" + i);
         r.Borders.LineStyle = Microsoft.Office.Interop.Excel.XlLineStyle.xlContinuous;
         r.Borders.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Black);
         // Lưu file
         SaveFileDialog dialog = new SaveFileDialog { FileName = "BCDocGia.xls", Filter = "Excel files|*.xls", DefaultExt = "xls", Title = "Chọn nơi lưu tệp báo cáo" };
         if (dialog.ShowDialog() == true)
         {
             exBook.SaveAs(dialog.FileName, COMExcel.XlFileFormat.xlWorkbookNormal,
                             null, null, false, false,
                             COMExcel.XlSaveAsAccessMode.xlExclusive,
                             false, false, false, false, false);
             MessageBox.Show("Xuất báo cáo thành công");
         }
         //
         exBook.Close(false, false, false);
         exApp.Quit();
         System.Runtime.InteropServices.Marshal.ReleaseComObject(exBook);
         System.Runtime.InteropServices.Marshal.ReleaseComObject(exApp);
         return true;
     }
     catch (Exception ex)
     {
         Console.WriteLine(ex.Message);
         return false;
     }
 }