Evaluation versions of yFiles.NET/WPF have a fixed expiration time (usually 30 days). If you try to use these assemblies after the expiration date, you'll receive a message stating that the evaluation period has expired, and the program is terminated.

This limit is hard coded into the product assemblies. Therefore, in order to switch from an evaluation version to a fully licensed one, it is sufficient to just replace the product assemblies, i.e. there are no registry entries or other hidden values that have to be reset. However, since building with Visual Studio copies the product assemblies to the output application folder (bin/Debug or bin/Release), you may still get the expiration message after upgrading to the fully licensed version.

The two most common problems when upgrading are:

Errors when running the bundled code samples or your own application inside Visual Studio

Visual Studio does not always detect when a referenced assembly has changed and will still try to execute the application with the evaluation version. Rebuilding the solution should fix the problem.

Errors when running an application outside Visual Studio

Update the assemblies in the application directory (usually the folder where the application itself resides) manually, e.g. copy the full versions from the shared yFiles product installation folder to this directory.

Checking the assembly status

The following code sample can be used to check whether you are actually using an evaluation version or a full version, as well as finding out the remaining evalution period:

using y.@base;
using yWorks.yFiles.UI.Model;

namespace EvalTester
{
  internal class EvalTester
  {
    public static void Main(string[] args) {
      //Check whether yFilesViewer is an evaluation version -
      //if yes AND the evaluation period is expired, you
      //will receive an error message, otherwise, the remaining 
      //evaluation period is printed.
      //
      //If you are using the yFiles.NET layout distribution, comment this out
      DefaultGraph graph = new DefaultGraph();

      //Check whether yFilesAlgorithm is an evaluation version -
      //if yes AND the evaluation period is expired, you
      //will receive an error message, otherwise, the remaining 
      //evaluation period is printed.
      //
      //If you are using the yFiles.NET/WPF Viewer distribution, comment this out
      Graph yGraph = new Graph();
    }
  }
}