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BarcodeReadSymbologyOperation Enumeration

Summary
Current barcode read operation.
Syntax
C#
Objective-C
C++/CLI
Java
Python
[SerializableAttribute()] 
public enum BarcodeReadSymbologyOperation   
typedef NS_ENUM(NSInteger, LTBarcodeReadSymbologyOperation) { 
 LTBarcodeReadSymbologyOperationPreRead,  
 LTBarcodeReadSymbologyOperationPostRead 
}; 
public enum BarcodeReadSymbologyOperation 
[SerializableAttribute()] 
public enum class BarcodeReadSymbologyOperation   
class BarcodeReadSymbologyOperation(Enum): 
   PreRead = 0 
   PostRead = 1 
Members
ValueMemberDescription
0PreRead

The BarcodeReader object is about to read the barcode symbologies.

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

1PostRead

The BarcodeReader has finished reading the barcode symbologies.

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

The resulting parameters are: The barcode data found which is in the Data property that 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).

Remarks

This enumeration is used as the type for the BarcodeReadSymbologyEventArgs.Operation property that can be used to determine the current barcode read stage.

Example
C#
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:\LEADTOOLS22\Resources\Images"; 
} 
Requirements

Target Platforms

Help Version 22.0.2023.5.9
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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.

Leadtools.Barcode Assembly
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.