LoadDocumentFromCache Event

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 LoadDocumentFromCache() 
{ 
   // The cache we are using 
   FileCache cache = new FileCache(); 
   cache.PolicySerializationMode = CacheSerializationMode.Json; 
   cache.DataSerializationMode = CacheSerializationMode.Json; 
   cache.CacheDirectory = @"c:\cache-dir"; 
 
   // document IDs to use 
   const string virtualDocumentId = "virtual"; 
   const string childDocumentId1 = "child1"; 
   const string childDocumentId2 = "child2"; 
 
   // Create a new document 
   var createDocumentOptions = new CreateDocumentOptions(); 
   createDocumentOptions.Cache = cache; 
   createDocumentOptions.DocumentId = virtualDocumentId; 
 
   using (LEADDocument document = DocumentFactory.Create(createDocumentOptions)) 
   { 
      document.Name = "Virtual"; 
      Debug.Assert(virtualDocumentId == document.DocumentId); 
 
      // Should have 0 pages and documents 
      Debug.Assert(document.Pages.Count == 0); 
      Debug.Assert(document.Documents.Count == 0); 
 
      // Add page 1 and 2 from a PDF file 
      var loadDocumentOptions = new LoadDocumentOptions(); 
      loadDocumentOptions.Cache = cache; 
      loadDocumentOptions.DocumentId = childDocumentId1; 
      LEADDocument childDocument = DocumentFactory.LoadFromFile(@"C:\LEADTOOLS22\Resources\Images\leadtools.pdf", loadDocumentOptions); 
      // Set the name 
      childDocument.Name = "Child1"; 
      childDocument.SaveToCache(); 
      // Now add the pages 
      document.Pages.Add(childDocument.Pages[0]); 
      document.Pages.Add(childDocument.Pages[1]); 
 
      // Add an empty page 
      DocumentPage documentPage = document.Pages.CreatePage(LeadSizeD.Create(LEADDocument.UnitsPerInch * 8.5, LEADDocument.UnitsPerInch * 11), 300); 
      document.Pages.Add(documentPage); 
 
      // Add page 3 and 4 from a TIF file 
      loadDocumentOptions = new LoadDocumentOptions(); 
      loadDocumentOptions.Cache = cache; 
      loadDocumentOptions.DocumentId = childDocumentId2; 
      childDocument = DocumentFactory.LoadFromFile(@"C:\LEADTOOLS22\Resources\Images\ocr1-4.tif", loadDocumentOptions); 
      // Set the name 
      childDocument.Name = "Child2"; 
      // Also save it into the cache 
      childDocument.SaveToCache(); 
      // Now add the pages 
      document.Pages.Add(childDocument.Pages[2]); 
      document.Pages.Add(childDocument.Pages[3]); 
 
      // Should have 5 pages and 2 documents (the PDF and the TIF) 
      Debug.Assert(document.Pages.Count == 5); 
      Debug.Assert(document.Documents.Count == 2); 
 
      // Tell the parent document to dispose any child documents when the parent is disposed 
      document.AutoDisposeDocuments = true; 
 
      // Now save, the parent document into the cache 
      document.SaveToCache(); 
 
      // And tell all documents to not delete themselves from the cache 
      document.AutoDeleteFromCache = false; 
   } 
 
   // Hook to the DocumentFactory.LoadDocumentFromCache event to log the documents being loaded 
   EventHandler<ResolveDocumentEventArgs> loadDocumentFromCacheHandler = (sender, e) => 
   { 
      Console.WriteLine("Loading child document from cache:"); 
      Console.WriteLine($" Source DocumentId:{e.SourceDocument.DocumentId}"); 
      Console.WriteLine($" DocumentId to load{e.LoadFromCacheOptions.DocumentId}"); 
      // Source document must be the virtual virtualDocumentId 
      Debug.Assert(virtualDocumentId == e.SourceDocument.DocumentId); 
      // Child documents being loaded is either childDocumentId1 or childDocumentId2 
      Debug.Assert(childDocumentId1 == e.LoadFromCacheOptions.DocumentId || childDocumentId2 == e.LoadFromCacheOptions.DocumentId); 
      // If this is childDocumentId2, we will load it ourselves, and change its name to indicate it has been loaded by us 
      if (childDocumentId2 == e.LoadFromCacheOptions.DocumentId) 
      { 
         // Modify e.LoadFromCacheOptions if needed, or create a new instance and use it 
         e.Document = DocumentFactory.LoadFromCache(e.LoadFromCacheOptions); 
         e.Document.Name = "LoadedByEvent"; 
      } 
      // else, let the factory loaded it normally 
   }; 
   DocumentFactory.LoadDocumentFromCache += loadDocumentFromCacheHandler; 
 
   // Now, load the document from the cache 
   var loadFromCacheOptions = new LoadFromCacheOptions(); 
   loadFromCacheOptions.Cache = cache; 
   loadFromCacheOptions.DocumentId = virtualDocumentId; 
   using (LEADDocument document = DocumentFactory.LoadFromCache(loadFromCacheOptions)) 
   { 
      Console.WriteLine($"Loaded virtual document id{document.DocumentId} name:{document.Name}"); 
      Debug.Assert(document.Name == "Virtual"); 
      // Should have 5 pages and 2 documents (the PDF and the TIF) 
      Debug.Assert(document.Pages.Count == 5); 
      Debug.Assert(document.Documents.Count == 2); 
 
      // Show the child document names, it should be Child1 and then LoadedByEvent 
      LEADDocument childDocument = document.Documents[0]; 
      Console.WriteLine($"First child document id{childDocument.DocumentId} name:{childDocument.Name}"); 
      Debug.Assert(childDocument.Name == "Child1"); 
      childDocument = document.Documents[1]; 
      Console.WriteLine($"Second child document id{childDocument.DocumentId} name:{childDocument.Name}"); 
      Debug.Assert(childDocument.Name == "LoadedByEvent"); 
   } 
 
   DocumentFactory.LoadDocumentFromCache -= loadDocumentFromCacheHandler; 
 
   // Done, delete all documents from the cache 
   bool isDeleted = DocumentFactory.DeleteFromCache(new LoadFromCacheOptions { Cache = cache, DocumentId = childDocumentId1 }); 
   Debug.Assert(isDeleted); 
   isDeleted = DocumentFactory.DeleteFromCache(new LoadFromCacheOptions { Cache = cache, DocumentId = childDocumentId2 }); 
   Debug.Assert(isDeleted); 
   isDeleted = DocumentFactory.DeleteFromCache(new LoadFromCacheOptions { Cache = cache, DocumentId = virtualDocumentId }); 
   Debug.Assert(isDeleted); 
}