File type associations

[Peter Aitken]

Can someone tell me how the registry stores the associations between file
types and programs? For example, TXT files are associated with Notepad.

 

[Mark V]

Can someone tell me how the registry stores the associations
between file types and programs? For example, TXT files are
associated with Notepad.

One method can be seen using cmd.exe commands: assoc and ftype
C:\TEMP>assoc .txt
.txt=txtfile

C:\TEMP>ftype txtfile
txtfile="C:\UTIL\EditPad.exe" "%1"

Which generally correspond to
HKEY_CLASSES_ROOT\.txt
HKEY_CLASSES_ROOT\txtfile

(HKEY_LOCAL_MACHINE\SOFTWARE\Classes)

And also possible:
HKEY_CURRENT_USER\Software\Classes

Some other methods may be used in some cases.

CPL, Folder Options, File types,
is the GUI interface.