title: How to scan driver's license (PDF417) using xamarin forms + zxing on iOS 10.2
body: <p>I am using Xamarin forms to write an iOS app and using the ZXing library to scan barcodes. I am trying to read a driver's license (PDF417) barcode, but the library is not able to recognize that barcode. </p>
  
  <p>If I include UPC or other barcodes in the PossibleFormats, they are scanned correctly.</p>
  
  <p>I am also certain the barcode I am trying to read is PDF417 barcode because Scandit is able to recognize it correctly while using only PDF417 barcode.</p>
  
  <p>Here is the code I am using. <strong>What do I need to change so that the PDF417 barcode is recognized correctly?</strong></p>
  
  <pre><code>async void Handle_Clicked (object sender, System.EventArgs e)
      {
          MobileBarcodeScanningOptions options = new MobileBarcodeScanningOptions ();
          options.PossibleFormats = new List&lt;ZXing.BarcodeFormat&gt; () {
              ZXing.BarcodeFormat.PDF_417
          };
          options.TryHarder = true;
  
          var scanPage = new ZXingScannerPage (options);
  
  
          scanPage.OnScanResult += (result) =&gt; {
              // Stop scanning
              scanPage.IsScanning = false;
  
              // Pop the page and show the result
              Device.BeginInvokeOnMainThread (async () =&gt; {
                  await Navigation.PopAsync ();
                  await DisplayAlert ("Scanned Barcode", result.Text, "OK");
              });
          };
  
          // Navigate to our scanner page
          await Navigation.PushAsync (scanPage);
      }
  </code></pre>