StringNullAllowed Property

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Ocr; 
using Leadtools.Document.Writer; 
 
public void OcrSettingManagerExample() 
{ 
   // Create an instance of the engine 
   using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD)) 
   { 
      // Start the engine using default parameters 
      ocrEngine.Startup(null, null, null, LEAD_VARS.OcrLEADRuntimeDir); 
 
      IOcrSettingManager settingManager = ocrEngine.SettingManager; 
 
      // Dump all the settings supported by this engine to a text file on disk 
      DumpAllSettings(settingManager); 
 
      // Image file to OCR 
      string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif"); 
 
      // File formats to save 
      DocumentFormat[] formats = { DocumentFormat.Text, DocumentFormat.Pdf }; 
 
      foreach (DocumentFormat format in formats) 
      { 
         // Generate the output file name 
         string outFileName = Path.ChangeExtension(tifFileName, DocumentWriter.GetFormatFileExtension(format)); 
 
         Console.WriteLine("Format: {0}\nOutput file: {1}", format, outFileName); 
 
         int detectFontStyles = 0; 
         bool recognizeFontAttributes = false; 
 
         if (format == DocumentFormat.Text) 
         { 
            // This is 'text' format, we dont need to recognize fonts attributes such as bold and italic 
            // This will make the recognition process faster 
 
            Console.WriteLine("Turning off font attributes"); 
 
            // Save the old settings 
            detectFontStyles = settingManager.GetEnumValue("Recognition.Fonts.DetectFontStyles"); 
            recognizeFontAttributes = settingManager.GetBooleanValue("Recognition.Fonts.RecognizeFontAttributes"); 
 
            // Turn them off now 
            settingManager.SetEnumValue("Recognition.Fonts.DetectFontStyles", "None"); 
            settingManager.SetBooleanValue("Recognition.Fonts.RecognizeFontAttributes", false); 
         } 
 
         // Show the settings we are using 
         Console.WriteLine("Recognizing using these font attributes settings:"); 
         Console.WriteLine("Recognition.Fonts.DetectFontStyles: {0}", settingManager.GetEnumValueAsString("Recognition.Fonts.DetectFontStyles")); 
         Console.WriteLine("Recognition.Fonts.RecognizeFontAttributes: {0}", settingManager.GetBooleanValue("Recognition.Fonts.RecognizeFontAttributes")); 
 
 
         // Recognize and save the file to the output format 
         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(outFileName, format, null); 
         } 
 
         // Re-set the original settings 
         if (format == DocumentFormat.Text) 
         { 
            Console.WriteLine("Resetting original settings"); 
            settingManager.SetEnumValue("Recognition.Fonts.DetectFontStyles", detectFontStyles); 
            settingManager.SetBooleanValue("Recognition.Fonts.RecognizeFontAttributes", recognizeFontAttributes); 
         } 
      } 
 
      // Shutdown the engine 
      // Note: calling Dispose will also automatically shutdown the engine if it has been started 
      ocrEngine.Shutdown(); 
   } 
} 
 
private static void DumpAllSettings(IOcrSettingManager settingManager) 
{ 
   // Write all the settings into a disk file 
   string settingsFileName = Path.Combine(LEAD_VARS.ImagesDir, "Settings.txt"); 
   using (StreamWriter writer = File.CreateText(settingsFileName)) 
   { 
      writer.WriteLine("Settings"); 
      string[] settingNames = settingManager.GetSettingNames(); 
 
      foreach (string settingName in settingNames) 
      { 
         IOcrSettingDescriptor sd = settingManager.GetSettingDescriptor(settingName); 
 
         writer.WriteLine("  Name:           {0}", sd.Name); 
         writer.WriteLine("  ValueType:      {0}", sd.ValueType); 
         writer.WriteLine("  FriendlyName:   {0}", sd.FriendlyName); 
 
         switch (sd.ValueType) 
         { 
            case OcrSettingValueType.BeginCategory: 
               writer.WriteLine("-------------------------------------"); 
               break; 
 
            case OcrSettingValueType.Integer: 
               writer.WriteLine("    Units: {0}", sd.Units); 
               writer.WriteLine("    IntegerMinimumValue: {0}", sd.IntegerMinimumValue); 
               writer.WriteLine("    IntegerMaximumValue: {0}", sd.IntegerMaximumValue); 
               break; 
 
            case OcrSettingValueType.Enum: 
               writer.WriteLine("    EnumIsFlags: {0}", sd.EnumIsFlags); 
               writer.WriteLine("    EnumMemberFriendlyNames"); 
               { 
                  int[] values = sd.GetEnumMemberValues(); 
                  string[] names = sd.GetEnumMemberFriendlyNames(); 
                  for (int i = 0; i < values.Length; i++) 
                  { 
                     writer.WriteLine("      {0} : {1}", names[i], values[i]); 
                  } 
               } 
               break; 
 
            case OcrSettingValueType.Double: 
               writer.WriteLine("    Units: {0}", sd.Units); 
               writer.WriteLine("    DoubleMinimumValue: {0}", sd.DoubleMinimumValue); 
               writer.WriteLine("    DoubleMaximumValue: {0}", sd.DoubleMaximumValue); 
               break; 
 
            case OcrSettingValueType.Boolean: 
               break; 
 
            case OcrSettingValueType.Character: 
               break; 
 
            case OcrSettingValueType.String: 
               writer.WriteLine("    StringMaximumLength:   {0}", sd.StringMaximumLength); 
               writer.WriteLine("    StringNullAllowed:     {0}", sd.StringNullAllowed); 
               break; 
 
            case OcrSettingValueType.Rectangle: 
               break; 
 
            case OcrSettingValueType.EndCategory: 
               break; 
 
            default: 
               break; 
         } 
      } 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
   public const string OcrLEADRuntimeDir = @"C:\LEADTOOLS23\Bin\Common\OcrLEADRuntime"; 
}