.cs C# "no results to display" when searching in windows explorer

[Guest]

I did a search in Windows Explorere on a directory that contained C# files
with file extension ".cs". The word I searched for was "Main". The search
program came back with a message "Search is complete. There are no results to
display". I renamed the ".cs" file to .txt and then did the search again.
This time the word "Main" was found in the file.

Why doesn't Search find words in ".cs" files?

Is there a way to make search find words in ".cs" files?

 

[Guest]

It's expected behavior for the search feature to only search within files
with an 'association' in the registry hive HKey_Classes_Root. (This means
they are assigned to open in some app)
Rightclick a .cs file, then 'open_with', and chose Notepad as the default
app to run .cs files when they are doubleclicked. (see checkbox to 'always
use this...)