Respect "UserChoice" registry key in wxFileType::GetOpenCommand()

[botg]

Changes made to file associations in Windows 7 through Explorer are not reflected by wxFileType::GetOpenCommand.

wx looks for the Progid value in HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\<ext>\ whereas Windows 7 stores the association in HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\<ext>\UserChoice

With the attached patch, the secon key is searched as well when getting the open command.

I have attached patches for both 2.8 as well as trunk.

[botg]

Reference to bug report:  http://forum.filezilla-project.org/viewtopic.php?f=5&t=16138

[vadz]

I've just tested it and creating a new association in the Explorer doesn't create User Choice subkey in the registry. It's true that some of the keys do have it but by no means all (in fact relatively few do) and I don't know what is it for. The officially sanctioned way is to add the progid of the program that can be used to open this type of files under OpenWithProgids subkey and AFAICS both Windows XP and Windows 7 do use it.

I think we should use it as well at least for the versions of Windows >= XP. BTW I have no idea where does the current code work because I don't see any progids directly under the extension subkey at all.

Do you have any documentation saying that UserChoice should be used? If not, I think we should use OpenWithProgids.

[botg]

Unfortunately I could not find any relevant information on the Microsoft website.

However, I found a pattern. It appears that the UserChoice key only appears on extensions that have multiple progids listed under OpenWithProgids.

I think the correct order is to first check UserChoice. If there is no such item, get the first value under OpenWithProgids (since there is no UserChoice, there should be at most one valye under OpenWithProgids). Last but not least, search all the other locations already searched by wx.

I'll update the patch accordingly later today.

[botg]

Here's the updated patch.

[vadz]

Should the trunk patch be modified in the same way?

TIA!

[vadz]

Tim, do you have any plans for upgrading the trunk version of the patch? TIA!

[vadz]

After more searching (2 years later there is still no official information about these keys) and experimenting, it seems that the only change needed in the trunk is to look under the correct key: as I wrote in comment:2, the current code simply looks for the ProgID in the wrong place.

As for using OpenWithProgids, it doesn't seem to be needed finally, as it's created only programmatically and all programs seem to create both it and the traditional keys under HKCR. So only UserChoice really needs to be taken into account.

[VZ]

(In [73106]) Correct lookup of Explorer-specific file association information.

The code added in r52154 never worked because it was looking for the Progid
value in a wrong place, look for it under UserChoice subkey where it really
is.

Also add a way to look up the command to open files with the given extension
to the exec sample.

Closes #12302.