How to associate a file extension to a program without making it the default program

Question

I'm deploying a small conversion tool on some systems, and want the users to be able to run it from the right click Open with menu. But I don't want to change the default program users have associated to this file type.

It is easy to associate a file extension/type to a program, but how to do it (programatically of course) without changing the default program?

Answer 1

You can add scripts to the context menu (below Open with) by adding it in the windows registry:

1. Open regedit
2. Goto HKEY_CLASSES_ROOT\your_class\Shell
3. Add a new key and give it a name
4. Edit the (Default) value of this key and insert the text you want to show in the context menu
5. Add a new key named Command under your newly created key
6. Edit the (Default) value of this key and insert the command you want to execute
7. Enjoy!

Answer 2

In the "File Types" Windows Dialog you can click "Advanced" on your file type and there create a custom action tied to your application.

Possibly you can also find a way to do this in a programmatic manner, or at least create a .REG file with the equivalent registry options.

Answer 3

here's a worked example for XP adding a command prompt option to folders. Create a .reg file

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\Directory\shell\Command Prompt]

[HKEY_CLASSES_ROOT\Directory\shell\Command Prompt\command] @="cmd.exe /k cd \"%1\""

Answer 4

Setting the following keys worked for me:

key HKLM/SOFTWARE/Microsoft/Windows/CurrentVersion/App Paths/<progname>: "" = <appPath>

key HKCR/Applications/<progname>/SupportedTypes: <fileExt> = ""
key HKCR/<fileExt>: "" = <progID>

key HKCR/<progID>/OpenWithList/<progName>
key HKCR/<fileExt>/OpenWithList/<progName>
key HKCR/SystemFileAssociations/<fileExt>/OpenWithList/<progName>

delete key and subkey at HKCU/SOFTWARE/Microsoft/Windows/CurrentVersion/Explorer/fileExts/<fileExt>