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Operation Property

Summary
Gets the current barcode read operation.
Syntax
C#
Objective-C
C++/CLI
Java
Python
public BarcodeReadSymbologyOperation Operation { get; } 
@property (nonatomic, assign, readonly) LTBarcodeReadSymbologyOperation operation 
public BarcodeReadSymbologyOperation getOperation() 
public: 
property BarcodeReadSymbologyOperation Operation { 
   BarcodeReadSymbologyOperation get(); 
} 
Operation # get  (BarcodeReadSymbologyEventArgs)

Property Value

A BarcodeReadSymbologyOperation enumeration member that specifies the current barcode read operation.

Remarks

The value of Operation is set by the BarcodeReader object as follows:

Value Description
BarcodeReadSymbologyOperation.PreRead

The BarcodeReader object is about to read the barcode symbologies in GetSymbologies.

The input parameters are: The symbologies to be read can be obtained through the GetSymbologies method and the associated read options are in the Options property.
BarcodeReadSymbologyOperation.PostRead

The BarcodeReader has finished reading the barcode symbologies.

The input parameters are: The symbologies to be read can be obtained through the GetSymbologies method and the associated read options are in the Options property.

The resulting parameters are: The barcode data found which is in the Data property and may contain a valid BarcodeData object or null (Nothing in Visual Basic) when an error occurs or no barcode of this type is found. In case of an error, the exception is in the Error property (Refer to BarcodeReader.ErrorMode for more information).
Example
C#
Java
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Barcode; 
using Leadtools.ImageProcessing; 
 
 
public void BarcodeReader_ReadSymbologyExample() 
{ 
   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)) 
      { 
         // Subscribe to the ReadSymbology event 
         reader.ReadSymbology += new EventHandler<BarcodeReadSymbologyEventArgs>(reader_ReadSymbology); 
         // Read all barcodes in the image 
         reader.ReadBarcodes(image, LeadRect.Empty, 0, null); 
         reader.ReadSymbology -= new EventHandler<BarcodeReadSymbologyEventArgs>(reader_ReadSymbology); 
      } 
   } 
} 
 
private void reader_ReadSymbology(object sender, BarcodeReadSymbologyEventArgs e) 
{ 
   if (e.Operation == BarcodeReadSymbologyOperation.PreRead) 
   { 
      // Before reading, show the symbologies the engine is going to try to read 
      Console.WriteLine("Trying to read the following symbologies:"); 
      BarcodeSymbology[] symbologies = e.GetSymbologies(); 
      for (int i = 0; i < symbologies.Length; i++) 
      { 
         Console.Write(symbologies[i]); 
         if (i != (symbologies.Length - 1)) 
         { 
            Console.Write(", "); 
            Console.WriteLine(e.Options.FriendlyName); 
         } 
         else 
         { 
            Console.WriteLine(); 
         } 
      } 
   } 
   else if (e.Operation == BarcodeReadSymbologyOperation.PostRead) 
   { 
      if (e.Error == null) 
      { 
         // No errors 
         BarcodeData barcode = e.Data; 
         if (barcode != null) 
         { 
            // Found a barcode, show it 
            Console.WriteLine("  {0} at {1} with data {2}", barcode.Symbology, barcode.Bounds, barcode.Value); 
         } 
         else 
         { 
            Console.WriteLine("  No barcodes found"); 
         } 
      } 
      else 
      { 
         // Show the error 
         Console.WriteLine("Error: {0}", e.Error.Message); 
 
         // Tell the reader top stop reading barcodes 
         e.Status = BarcodeReadSymbologyStatus.Abort; 
      } 
   } 
} 
 
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; 
 
 
public void barcodeReaderReadSymbologyExample() { 
   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); 
   codecs.save(image, "Result.jpg", RasterImageFormat.JPEG, 0); 
 
   // Subscribe to the ReadSymbology event 
   reader.addReadSymbologyListener(readerReadSymbology); 
 
   // Read all barcodes in the image 
   reader.readBarcodes(image, LeadRect.getEmpty(), 0, null); 
   reader.removeReadSymbologyListener(readerReadSymbology); 
 
   assertTrue("Image unsuccessfully saved", (new File("Result.jpg")).exists()); 
   System.out.printf("Image loaded and saved to %s%n", new File("Result.jpg")); 
} 
 
BarcodeReadSymbologyListener readerReadSymbology = new BarcodeReadSymbologyListener() { 
 
   @Override 
   public void onReadSymbologyEvent(BarcodeReadSymbologyEvent arg0) { 
 
      if (arg0.getOperation() == BarcodeReadSymbologyOperation.PRE_READ) { 
 
         // Before reading, show the symbologies the engine is going to try to read 
         System.out.println("Trying to read the following symbologies:"); 
         BarcodeSymbology[] symbologies = arg0.getSymbologies(); 
 
         for (int i = 0; i < symbologies.length; i++) { 
            System.out.print(symbologies[i]); 
 
            if (i != (symbologies.length - 1)) { 
               System.out.print(", "); 
               System.out.println(arg0.getOptions().getFriendlyName()); 
 
            } else { 
               System.out.println(" "); 
            } 
         } 
      } 
 
      else if (arg0.getOperation() == BarcodeReadSymbologyOperation.POST_READ) { 
 
         if (arg0.getError() == null) { 
 
            // No errors 
            BarcodeData barcode = arg0.getData(); 
 
            if (barcode != null) { 
 
               // Found a barcode, show it 
               System.out.printf("  %1s at %2s with data %3s%n", barcode.getSymbology(), barcode.getBounds(), 
                     barcode.getValue()); 
            } else { 
               System.out.println("  No barcodes found"); 
            } 
         } else { 
            // Show the error 
            System.out.printf("Error: %1s%n", arg0.getError().getMessage()); 
 
            // Tell the reader top stop reading barcodes 
            arg0.setStatus(BarcodeReadSymbologyStatus.ABORT); 
         } 
      } 
   } 
 
};
Requirements

Target Platforms

Help Version 23.0.2024.2.29
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Leadtools.Barcode Assembly
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