Script to associate an extension to a program

The real association is stored in the key that "HKEY_CLASSES_ROOT\.xml" points to.

On my machine, the default value of that key says "xmlfile", most likely that is the same for yours.

So let's go to "HKEY_CLASSES_ROOT\xmlfile". There you can see (and change) what command is going to be used to launch that type of file:

HKEY_CLASSES_ROOT\xmlfile\shell\open\command

Windows uses this kind of redirection to map multiple file extensions to the same file type, and thus to the same application.

Under "HKEY_CLASSES_ROOT\xmlfile\shell" there are multiple sub-keys that resemble the "verbs" of what you can do to the file. Again, the default value of the "shell" key decides which of these verbs is used if you double click the file. In my case this is "open".

Conclusion:

With that knowledge, the easiest way to make an association scriptable is to use regedit to export a .reg file containing that change, and apply it to the target computer with a double click or:

regedit /s new_xml_association.reg

or (if you are on XP or higher and know what you do) overwrite the current value with:

reg add "HKEY_CLASSES_ROOT\xmlfile\shell\open\command" /ve /d "path\to\program %1"

At any rate, a deeper look into reg add/? command is advised. The first solution is safer.

consider the dos command assoc:

C:>assoc /? Displays or modifies file extension associations

ASSOC [.ext[=[fileType]]]

.ext Specifies the file extension to associate the file type with fileType Specifies the file type to associate with the file extension

Type ASSOC without parameters to display the current file associations. If ASSOC is invoked with just a file extension, it displays the current file association for that file extension. Specify nothing for the file type and the command will delete the association for the file extension.

Using file associations in this case seems like the wrong thing to do. You want your application to open the file in OpenOffice but what if your user wants to leave the file association for XML files untouched? What if something else on their system also relies on that association? You are breaking their system in that case. If you are the IT person then perhaps that is OK (still questionable programming practice), but if not then this is a bad thing to do.

Use the OpenOffice COM implementation to open the file instead.

Good simple example here: http://www.kalitech.fr/clients/doc/VB_APIOOo_en.html