FAQ: Why does OCR Advantage code work in Winforms but not ASP.NET?

Sometimes the exact same code for the OCR Advantage engine will work perfectly fine in a Winforms application but not an ASP.NET application.  It will usually throw an exception like "Could not load file or assembly 'Leadtools, Version=16.5.0.0..."  To fix this problem, set the Recognition.Zoning.DisableMultiThreading setting to True.

The reason you must do this is because the description of this setting in the documentation states: "Multi-threading enhances the performance of the auto-zoning algorithm.  However, it may be undesirable if the OCR engine is hosted in a server."

For more details on other settings, their advantages, uses, and limitations, please check out the following help file articles:

LEADTOOLS OCR Advantage Engine Settings
LEADTOOLS OCR Plus Engine Settings
LEADTOOLS OCR Professional Engine Settings

Another workaround for this is to add the LEADTOOLS DLLs into the GAC and you will be able to use multi-threading (the default options).