ErrorMode Property

Summary

Indicate how to handle errors when reading barcodes.

Syntax

Objective-C

C++/CLI

Java

Python

public BarcodeReaderErrorMode ErrorMode { get; set; }

@property (nonatomic, assign) LTBarcodeReaderErrorMode errorMode;

public BarcodeReaderErrorMode getErrorMode() 
public void setErrorMode(BarcodeReaderErrorMode value)

public: 
property BarcodeReaderErrorMode ErrorMode { 
   BarcodeReaderErrorMode get(); 
   void set (    BarcodeReaderErrorMode ); 
}

ErrorMode # get and set (BarcodeReader)

Property Value

An BarcodeReaderErrorMode enumeration member that indicates how to handle errors when reading barcodes. The default value is BarcodeReaderErrorMode.Default.

Remarks

The BarcodeReader object might encounter errors when reading barcodes. By default, when an error is encountered, an exception is thrown, usually of type BarcodeException with the BarcodeException.Code set to one of the BarcodeExceptionCode enumeration members for more details regarding the error. This is the default behavior.

Sometimes, this behavior is not the desired one, for example:

The application is trying to decode barcodes on an "if found and correct" basis. If there were corrupted barcodes, the action is to ignore them and to continue. In this case, you can set the error mode to BarcodeReaderErrorMode.IgnoreAll.

The application is reading multiple barcodes from an image, and the action is to ignore the corrupted barcodes and return only the valid ones found. In this case, you can set the error mode to BarcodeReaderErrorMode.IgnoreAll and subscribe to the BarcodeReader.ReadSymbology event to get a notification when an error occurs and save the exception for later use. You can then handle these errors when all barcodes are read and the read method returns.

The LEADTOOLS C# Barcode Demo changes the value of ErrorMode to BarcodeReaderErrorMode.IgnoreAll and uses the BarcodeReader.ReadSymbology event to show the errors encountered in a list box.

Note that when the BarcodeReader does not find any barcodes in the image, no exception is thrown. Instead, BarcodeReader.ReadBarcode and BarcodeReader.ReadBarcodes methods will return null (Nothing in VB) or an empty array of BarcodeData type.

Example

This example changes the value of BarcodeReader.ErrorMode before reading all the barcodes from an image. It will then show any errors encountered after the read operation returns.

Java

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Barcode; 
using Leadtools.ImageProcessing; 
 
 
private List<Exception> myErrors;   // List of errors 
 
public void BarcodeReader_ErrorModeExample() 
{ 
   string imageFileName = Path.Combine(LEAD_VARS.ImagesDir, "Barcode1.tif"); 
 
   // Create a Barcode engine 
   BarcodeEngine engine = new BarcodeEngine(); 
 
   // Get the Barcode reader instance 
   BarcodeReader reader = engine.Reader; 
 
   // Load the image 
   using (RasterCodecs codecs = new RasterCodecs()) 
   { 
      using (RasterImage image = codecs.Load(imageFileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1)) 
      { 
         myErrors = new List<Exception>(); 
 
         // Disable the errors 
         reader.ErrorMode = BarcodeReaderErrorMode.IgnoreAll; 
 
         // Subscribe to the ReadSymbology event 
         reader.ReadSymbology += new EventHandler<BarcodeReadSymbologyEventArgs>(myReader_ReadSymbology); 
         // Read all barcodes in the image 
         reader.ReadBarcodes(image, LeadRect.Empty, 0, null); 
         reader.ReadSymbology -= new EventHandler<BarcodeReadSymbologyEventArgs>(myReader_ReadSymbology); 
 
         // Show the errors 
         if (myErrors.Count > 0) 
         { 
            Console.WriteLine("Errors encountered:"); 
            foreach (Exception error in myErrors) 
            { 
               Console.WriteLine(error.Message); 
            } 
         } 
      } 
   } 
} 
 
private void myReader_ReadSymbology(object sender, BarcodeReadSymbologyEventArgs e) 
{ 
   // If we encounter an error, save it to our list 
   if (e.Error != null) 
   { 
      myErrors.Add(e.Error); 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}

 
import java.io.File; 
import java.io.IOException; 
import java.util.*; 
import java.util.concurrent.ExecutorService; 
import java.util.concurrent.Executors; 
 
import org.junit.*; 
import org.junit.Test; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
import static org.junit.Assert.*; 
 
import leadtools.*; 
import leadtools.barcode.*; 
import leadtools.codecs.*; 
import leadtools.imageprocessing.*; 
import leadtools.internal.ManualResetEvent; 
 
 
private List<Exception> myErrors; // List of errors 
 
public void barcodeReaderErrorModeExample() { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   String imageFileName = combine(LEAD_VARS_IMAGES_DIR, "barcode1.tif"); 
 
   // Create a Barcode engine 
   BarcodeEngine engine = new BarcodeEngine(); 
 
   // Get the Barcode reader instance 
   BarcodeReader reader = engine.getReader(); 
 
   // Load the image 
   RasterCodecs codecs = new RasterCodecs(); 
 
   RasterImage image = codecs.load(imageFileName, 0, CodecsLoadByteOrder.BGR_OR_GRAY, 1, 1); 
 
   myErrors = new ArrayList<Exception>(); 
 
   // Disable the errors 
   reader.setErrorMode(BarcodeReaderErrorMode.IGNORE_ALL); 
 
   // Subscribe to the ReadSymbology event 
   reader.addReadSymbologyListener(myReaderReadSymbology); 
 
   // Read all barcodes in the image 
   reader.readBarcodes(image, LeadRect.getEmpty(), 0, null); 
   reader.removeReadSymbologyListener(myReaderReadSymbology); 
 
   // Show the errors 
   if (myErrors.size() > 0) { 
      System.out.println("Errors encountered:"); 
      for (Exception error : myErrors) { 
         System.out.println(error.getMessage()); 
      } 
   } 
 
   String outputFileName = combine(LEAD_VARS_IMAGES_DIR, "Result.jpg"); 
   codecs.save(image, outputFileName, RasterImageFormat.JPEG, 0); 
 
   assertTrue("Image unsuccessfully saved to " + outputFileName, (new File(outputFileName)).exists()); 
   System.out.printf("Image successfully saved to %s%n", outputFileName); 
} 
 
BarcodeReadSymbologyListener myReaderReadSymbology = new BarcodeReadSymbologyListener() { 
 
   @Override 
   public void onReadSymbologyEvent(BarcodeReadSymbologyEvent arg0) { 
      if (arg0.getError() != null) { 
         myErrors.add(arg0.getError()); 
      } 
   } 
 
};

Requirements

Target Platforms

Reference

BarcodeReader Class

BarcodeReader Members

Download our FREE evaluation

Help Version 23.0.2024.2.29

Leadtools.Barcode Assembly

Introduction

Getting Started

Namespaces

Leadtools.Barcode Namespace

Assemblies