search a given word in word file by Aspose
Some quick remarks:

FindContentOfWordDoc is a bad class name, in the first place because it contains a verb. Please follow the Microsoft rules.

While this code only does a search, it is peppered with names that refer to &quot;find and replace&quot;. This makes it hard to understand. I assume this must be due to Aspose, so perhaps this is inevitable, but then perhaps you could add some comments to explain why you implemented it this way.
Are you certain this is the best way to execute a search? I find it odd that you would need to &quot;abuse&quot; the &quot;find and replace&quot; functionality; it seems odd that Aspose would include that functionality yet not a &quot;find&quot; on its own.

You don't check content: is this function only intended for single word queries, or also for combinations of words? And why not check if the user actually entered a search term, in order to avoid invoking the callback etc. on a null or an empty string?