Clear Method

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Document.Writer; 
 
using Leadtools.Document; 
using Leadtools.Caching; 
using Leadtools.Annotations.Engine; 
using Leadtools.Ocr; 
using Leadtools.Barcode; 
using Leadtools.Document.Converter; 
 
public void DocumentHistoryExample() 
{ 
   // Setup a cache 
   FileCache cache = new FileCache(); 
   cache.CacheDirectory = @"c:\cache-dir"; 
 
   // Create a new document 
   var createOptions = new CreateDocumentOptions(); 
   const string documentId = "virtual"; 
   createOptions.Cache = cache; 
   createOptions.DocumentId = documentId; 
 
   using (var document = DocumentFactory.Create(createOptions)) 
   { 
      document.Name = "Virtual"; 
      // DocumentHistory reference 
      document.History.AutoUpdate = true; 
      document.IsReadOnly = false; 
 
      // Show its history 
      ShowHistory("virtual", document); 
 
      // Ensure it has no pages 
      Debug.Assert(document.Pages.Count == 0); 
      Debug.Assert(document.Documents.Count == 0); 
 
      // Add some pages 
 
      // First add the first 2 pages from a PDF file 
      var loadOptions = new LoadDocumentOptions(); 
      loadOptions.Cache = cache; 
      LEADDocument childDocument = DocumentFactory.LoadFromUri(new Uri("https://demo.leadtools.com/images/pdf/leadtools.pdf"), loadOptions); 
      childDocument.AutoDeleteFromCache = false; 
      childDocument.SaveToCache(); 
      childDocument.Annotations.SetHistory(childDocument.Annotations.GetHistory()); 
      document.Pages.Add(childDocument.Pages[0]); 
      document.Pages.Add(childDocument.Pages[1]); 
 
      // Add an empty page 
      var documentPage = document.Pages.CreatePage(LeadSizeD.Create(LEADDocument.UnitsPerInch * 8.5, LEADDocument.UnitsPerInch * 11), 300); 
      document.Pages.Add(documentPage); 
 
      // Add last 2 pages from a TIFF file 
 
      childDocument = DocumentFactory.LoadFromUri(new Uri("https://demo.leadtools.com/images/pdf/leadtools.pdf"), loadOptions); 
      childDocument.AutoDeleteFromCache = false; 
      childDocument.SaveToCache(); 
      document.Pages.Add(childDocument.Pages[2]); 
      document.Pages.Add(childDocument.Pages[3]); 
 
      // Check the document 
      Debug.Assert(5 == document.Pages.Count); 
      Debug.Assert(2 == document.Documents.Count); 
 
      // Get each DocumentHistoryItem 
      foreach (DocumentHistoryItem item in document.History.GetItems()) 
      { 
         document.History.SetItems(null); 
         Console.WriteLine(item); 
      } 
 
      // Enumerate through DocumentHistoryModifyType 
      DocumentHistoryModifyType[] modifyType = (DocumentHistoryModifyType[])Enum.GetValues(typeof(DocumentHistoryModifyType)); 
      foreach (var type in modifyType) 
      { 
         Console.WriteLine($"Type of modification: {type}"); 
      } 
 
      document.AutoDisposeDocuments = true; 
      document.AutoDeleteFromCache = false; 
      document.SaveToCache(); 
   } 
 
   // Load it and show its history 
   var loadFromCacheOptions = new LoadFromCacheOptions(); 
   loadFromCacheOptions.Cache = cache; 
   loadFromCacheOptions.DocumentId = documentId; 
   using (var document = DocumentFactory.LoadFromCache(loadFromCacheOptions)) 
   { 
      ShowHistory("virtual pages added", document); 
 
      // Clear the history 
      document.History.Clear(); 
   } 
 
   // Now, load the document from the cache 
   using (var document = DocumentFactory.LoadFromCache(loadFromCacheOptions)) 
   { 
      Debug.Assert(5 == document.Pages.Count); 
      Debug.Assert(2 == document.Documents.Count); 
 
      // Remove some pages 
      document.Pages.RemoveAt(0); 
      document.Pages.RemoveAt(document.Pages.Count - 1); 
      // And rotate another 
      document.Pages[1].Rotate(90); 
 
      Debug.Assert(3 == document.Pages.Count); 
      Debug.Assert(2 == document.Documents.Count); 
 
      ShowHistory("virtual pages removed and rotated", document); 
   } 
 
   // Clean up 
   var deleteFromCacheOptions = new LoadFromCacheOptions(); 
   deleteFromCacheOptions.Cache = cache; 
   deleteFromCacheOptions.DocumentId = documentId; 
   DocumentFactory.DeleteFromCache(deleteFromCacheOptions); 
} 
 
private static void ShowHistory(string message, LEADDocument document) 
{ 
   Console.WriteLine("History " + message); 
   var items = document.History.GetItems(); 
   foreach (var item in items) 
   { 
      Console.WriteLine("  user:{0} timestamp:{1} comment:{2} modifyType:{3} pageNumber:{4}", 
         item.UserId, item.Timestamp, item.Comment, item.ModifyType, item.PageNumber); 
   } 
}