How to migrate to GroupDocs.Viewer 19.8 or higher

This article contains information about migration from the legacy API to GroupDocs.Viewer 19.8 or higher.

Why To Migrate

Here are the key reasons to use the new updated API provided by GroupDocs.Viewer for .NET since version 19.8:

  • Viewer class introduced as a single entry point to manage the document rendering process to any supported file format (instead of ViewerHtmlHander / ViewerImageHander classes from previous versions).
  • The overall rendering speed improved dramatically by saving rendered page as soon as it was rendered, not when all pages list were rendered.
  • Product architecture was redesigned from scratch in order to decreased memory usage (from 10% to 400% approx. depending on document type).
  • Document rendering options simplified so it’s easy to instantiate proper options class and control over document rendering and saving processes.

How To Migrate

Here is a brief comparison of how to display document into HTML form using old and new API.

Old coding style

//Get Configurations
ViewerConfig config = Utilities.GetConfigurations();

// Create html handler
ViewerHtmlHandler htmlHandler = new ViewerHtmlHandler(config);

// Guid implies that unique document name 
string guid = "sample.docx";

//Instantiate the HtmlOptions object
HtmlOptions options = new HtmlOptions();

//to get html representations of pages with embedded resources
options.IsResourcesEmbedded = true;

// Set password if document is password protected. 
   options.Password = DocumentPassword;
//Get document pages in html form
List<PageHtml> pages = htmlHandler.GetPages(guid, options);

foreach (PageHtml page in pages)
    //Save each page at disk
    Utilities.SaveAsHtml(page.PageNumber + "_" + DocumentName, page.HtmlContent);

New coding style

using (Viewer viewer = new Viewer("sample.docx"))
   HtmlViewOptions options = HtmlViewOptions.ForEmbeddedResources();

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