Hi,

We do not officially support such features directly through our API. However we can provide you some implementations details regarding Chromium's dictionary so that you may be able to implement this in your own code.

1. Chromium uses two separate dictionary files. The main dictionary file is in "AppData\Local\EO.WebEngine\User Data\Dictionaries" folder. The dictionary is automatically downloaded from Google if one does not exist. The download can fail due to various reasons: network access, local file permissions, etc. When that fail, you will not get the dictionary file and spell checker will fail on every word. If you run into such issue, you can make sure the file exists in that folder;

2. There is a separate dictionary file named "Custom Dictionary.txt" inside the browser engine's cache file path. This file contains user added words. By default the browser engine's temp file path is in "AppData\Local\Local\Temp\eo.webbrowser.cache.xxxx" where "xxxx" can vary depending on EO.WebBrowser version number and a number of other factors. The easiest way for you to get this path is through this property:

https://www.essentialobjects.com/doc/eo.webengine.engine.cachepath.aspx

The file contains custom words one word per line, then one additional line that contains the MD5 checksum of all the previous lines. You can reference the chromium source code that reads/writes this file for more details:

https://cs.chromium.org/chromium/src/chrome/browser/spellchecker/spellcheck_custom_dictionary.cc

So in theory it's possible for you to create a file with all your custom words and place it inside the cache path and they should be automatically picked up by the spell checker.

Hope this helps.

Thanks!