OcrException Class

C#
Visual Basic
WinRT C#
Java
Objective-C
WinRT JavaScript
C++

[SerializableAttribute()]
public class OcrException : System.Exception, System.Runtime.InteropServices._Exception, System.Runtime.Serialization.ISerializable

'Declaration

<SerializableAttribute()>
Public Class OcrException 
   Inherits System.Exception
   Implements System.Runtime.InteropServices._Exception, System.Runtime.Serialization.ISerializable

'Usage

Dim instance As OcrException

public sealed class OcrException : System.Runtime.InteropServices._Exception, ~Remove~

public class OcrException extends RuntimeException

function Leadtools.Forms.Ocr.OcrException()

[SerializableAttribute()]
public ref class OcrException : public System.Exception, System.Runtime.InteropServices._Exception, System.Runtime.Serialization.ISerializable

When a runtime error occurs in the IOcrEngine, an exception of type OcrException is thrown with the engine-specific error code set in the Code member. This error code is engine-specific but a short description can be obtained using the Message property of this class or by using the IOcrEngine.GetErrorCodeString method.

Logic errors such as invalid parameters to methods or invalid operations throw standard .NET exceptions (in this case, ArgumentException and InvalidOperationException respectively Errors caused by loading invalid image files using IOcrEngine.RasterCodecsInstance will throw exceptions of type RasterException. Errors for missing features (support locked) will throw OcrSupportLockedException exceptions. Any other runtime error in the engine will throw an OcrException.

This example shows how to trap various types of exceptions during OCR operations.

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms.Ocr
Imports Leadtools.Forms.DocumentWriters

<TestMethod>
Public Sub OcrExceptionExample()
   Try
      ' Create an instance of the engine
      Using ocrEngine As IOcrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Advantage, False)
         ' Start the engine using default parameters
         ocrEngine.Startup(Nothing, Nothing, Nothing, LEAD_VARS.OcrAdvantageRuntimeDir)
         Dim tifFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif")
         Dim pdfFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.pdf")

         ' Create a page
         ' Create an OCR document
         Using ocrDocument As IOcrDocument = ocrEngine.DocumentManager.CreateDocument()
            ' Add a page to the document
            Dim ocrPage As IOcrPage = ocrDocument.Pages.AddPage(tifFileName, Nothing)

            ' Recognize the page
            ' Note, Recognize can be called without calling AutoZone or manually adding zones. The engine will
            ' check and automatically auto-zones the page
            ocrPage.Recognize(Nothing)

            ' Save the document we have as PDF
            ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, Nothing)
         End Using

         ' Shutdown the engine
         ' Note: calling Dispose will also automatically shutdown the engine if it has been started
         ocrEngine.Shutdown()
      End Using
   Catch ex As OcrSupportLockedException
      Console.WriteLine("Support is locked. You need to unlock '{0}' in this engine to use this feature", ex.SupportType)
   Catch ex As OcrException
      Console.WriteLine("OCR Error" & vbLf & "Code: {0}" & vbLf & "Message:{1}", ex.Code, ex.Message)
   Catch ex As RasterException
      Console.WriteLine("LEADTOOLS Error" & vbLf & "Code: {0}" & vbLf & "Message:{1}", ex.Code, ex.Message)
   Catch ex As Exception
      Console.WriteLine("System Error" & vbLf & "Message:{0}", ex.Message)
   End Try
End Sub

Public NotInheritable Class LEAD_VARS
Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
Public Const OcrAdvantageRuntimeDir As String = "C:\LEADTOOLS 19\Bin\Common\OcrAdvantageRuntime"
End Class

using Leadtools;
using Leadtools.Codecs;
using Leadtools.Forms.Ocr;
using Leadtools.Forms.DocumentWriters;

public void OcrExceptionExample()
{
   try
   {
      // Create an instance of the engine
      using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Advantage, false))
      {
         // Start the engine using default parameters
         ocrEngine.Startup(null, null, null, LEAD_VARS.OcrAdvantageRuntimeDir);
         string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif");
         string pdfFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.pdf");

         // Create a page
         // Create an OCR document
         using (IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument())
         {
            // Add a page to the document
            IOcrPage ocrPage = ocrDocument.Pages.AddPage(tifFileName, null);

            // Recognize the page
            // Note, Recognize can be called without calling AutoZone or manually adding zones. The engine will
            // check and automatically auto-zones the page
            ocrPage.Recognize(null);

            // Save the document we have as PDF
            ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, null);
         }

         // Shutdown the engine
         // Note: calling Dispose will also automatically shutdown the engine if it has been started
         ocrEngine.Shutdown();
      }
   }
   catch (OcrSupportLockedException ex)
   {
      Console.WriteLine("Support is locked. You need to unlock '{0}' in this engine to use this feature", ex.SupportType);
   }
   catch (OcrException ex)
   {
      Console.WriteLine("OCR Error\nCode: {0}\nMessage:{1}", ex.Code, ex.Message);
   }
   catch (RasterException ex)
   {
      Console.WriteLine("LEADTOOLS Error\nCode: {0}\nMessage:{1}", ex.Code, ex.Message);
   }
   catch (Exception ex)
   {
      Console.WriteLine("System Error\nMessage:{0}", ex.Message);
   }
}

static class LEAD_VARS
{
public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
public const string OcrAdvantageRuntimeDir = @"C:\LEADTOOLS 19\Bin\Common\OcrAdvantageRuntime";
}

Target Platforms

Reference

OcrException Members
Leadtools.Forms.Ocr Namespace
IOcrEngine.Startup
IOcrEngine.IsStarted
IOcrEngine.Shutdown
OcrEngineManager Class
OcrEngineType Enumeration
Programming with LEADTOOLS .NET OCR