Leadtools.Barcode Namespace > BarcodeReader Class : ErrorMode Property |
public BarcodeReaderErrorMode ErrorMode {get; set;}
'Declaration Public Property ErrorMode As BarcodeReaderErrorMode
'Usage Dim instance As BarcodeReader Dim value As BarcodeReaderErrorMode instance.ErrorMode = value value = instance.ErrorMode
public BarcodeReaderErrorMode ErrorMode {get; set;}
@property (nonatomic, assign) LTBarcodeReaderErrorMode errorMode;
public BarcodeReaderErrorMode getErrorMode() public void setErrorMode(BarcodeReaderErrorMode value)
get_ErrorMode();
set_ErrorMode(value);
Object.defineProperty('ErrorMode');
public: property BarcodeReaderErrorMode ErrorMode { BarcodeReaderErrorMode get(); void set ( BarcodeReaderErrorMode value); }
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# and VB 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 Visual Basic) or an empty array of BarcodeData type.
Imports Leadtools Imports Leadtools.Codecs Imports Leadtools.Forms Imports Leadtools.Barcode Imports Leadtools.ImageProcessing Private myErrors As List(Of Exception) ' List of errors Public Sub BarcodeReader_ErrorModeExample() Dim imageFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Barcode1.tif") ' Create a Barcode engine Dim engine As New BarcodeEngine() ' Get the Barcode reader instance Dim reader As BarcodeReader = engine.Reader ' Load the image Using codecs As New RasterCodecs() Using image As RasterImage = codecs.Load(imageFileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1) myErrors = New List(Of Exception)() ' Disable the errors reader.ErrorMode = BarcodeReaderErrorMode.IgnoreAll ' Subscribe to the ReadSymbology event AddHandler reader.ReadSymbology, AddressOf myReader_ReadSymbology ' Read all barcodes in the image reader.ReadBarcodes(image, LogicalRectangle.Empty, 0, Nothing) RemoveHandler reader.ReadSymbology, AddressOf myReader_ReadSymbology ' Show the errors If myErrors.Count > 0 Then Console.WriteLine("Errors encountered:") For Each err As Exception In myErrors Console.WriteLine(err.Message) Next End If End Using End Using End Sub Private Sub myReader_ReadSymbology(ByVal sender As Object, ByVal e As BarcodeReadSymbologyEventArgs) ' If we encounter an error, save it to our list If Not IsNothing(e.Error) Then myErrors.Add(e.Error) End If End Sub Public NotInheritable Class LEAD_VARS Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" End Class
using Leadtools; using Leadtools.Codecs; using Leadtools.Forms; 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, LogicalRectangle.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:\Users\Public\Documents\LEADTOOLS Images"; }
using Leadtools; using Leadtools.Codecs; using Leadtools.Barcode; using Leadtools.ImageProcessing; private List<BarcodeException> myErrors; // List of errors public async Task BarcodeReader_ErrorModeExample() { string imageFileName = @"Assets\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()) { StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(imageFileName); using(RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile))) { myErrors = new List<BarcodeException>(); // 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, LeadRectHelper.Empty, 0, null); reader.ReadSymbology -= new EventHandler<BarcodeReadSymbologyEventArgs>(myReader_ReadSymbology); // Show the errors if(myErrors.Count > 0) { Debug.WriteLine("Errors encountered:"); foreach(BarcodeException error in myErrors) { Debug.WriteLine(error.Message); } } } } } private void myReader_ReadSymbology(object sender, BarcodeReadSymbologyEventArgs e) { // If we encounter an error, save it to our list BarcodeException barcodeException = BarcodeException.FromHResult(e.HResult); if (barcodeException != null) { myErrors.Add(barcodeException); } }
using Leadtools; using Leadtools.Codecs; using Leadtools.Forms; using Leadtools.Barcode; using Leadtools.ImageProcessing; using Leadtools.Examples; private List<Exception> myErrors; // List of errors public void BarcodeReader_ErrorModeExample(RasterImage image) { // Create a Barcode engine BarcodeEngine engine = new BarcodeEngine(); // Get the Barcode reader instance BarcodeReader reader = engine.Reader; // Load the image RasterCodecs codecs = new RasterCodecs(); 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, LogicalRectangle.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); } }
Imports Leadtools Imports Leadtools.Codecs Imports Leadtools.Forms Imports Leadtools.Barcode Imports Leadtools.ImageProcessing Imports Leadtools.ImageProcessing.Color Private myErrors As List(Of Exception) ' List of errors Public Sub BarcodeReader_ErrorModeExample(ByVal image As RasterImage) ' Create a Barcode engine Dim engine As BarcodeEngine = New BarcodeEngine() ' Get the Barcode reader instance Dim reader As BarcodeReader = engine.Reader ' Load the image Dim codecs As RasterCodecs = New RasterCodecs() myErrors = New List(Of Exception)() ' Disable the errors reader.ErrorMode = BarcodeReaderErrorMode.IgnoreAll ' Subscribe to the ReadSymbology event AddHandler reader.ReadSymbology, AddressOf myReader_ReadSymbology ' Read all barcodes in the image reader.ReadBarcodes(image, LogicalRectangle.Empty, 0, Nothing) RemoveHandler reader.ReadSymbology, AddressOf myReader_ReadSymbology ' Show the errors If myErrors.Count > 0 Then Console.WriteLine("Errors encountered:") For Each [error] As Exception In myErrors Console.WriteLine([error].Message) Next End If End Sub Private Sub myReader_ReadSymbology(ByVal sender As Object, ByVal e As BarcodeReadSymbologyEventArgs) ' If we encounter an error, save it to our list If Not e.Error Is Nothing Then myErrors.Add(e.Error) End If End Sub