LoadDocumentFromCache Event (original) (raw)
Summary
Called by the factory when loading child documents from the cache.
Syntax
def LoadDocumentFromCache(sender,e): # sender: DocumentFactory e: ResolveDocumentEventArgs Example
This example will create a document from child documents, save it to the cache, and then re-load it. It will use the LoadDocumentFromCache event to manually load the child documents.
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);
}