How to open a xdp-file with the default command for opening a pdf-file


I want open a file with an xdp-extention with the default program for a pdf-file.
I can't change the default program to open an xdp-file because that has stay another program (designing program)
So if i dubbelclick the xdp-file it has to open in the designer (default from installation) but if I open the file from my program (shellexecute) I want to open it with the default pdf-program.
Most of the time this will be a version of Acrobat but it can be another one.

I never know for sure what version of Acrobat the users have.
I looked in the registry to find out how windows opens a pdf-file by default and I think its the following
if I look at HKLM\SOFTWARE\Classes\.pdf I see the default is Acroexch.Document
then I get the command from HKLM\SOFTWARE\Classes\AcroExch.Document\Shell\open\command

Now if i use that key in the shellexecute everything works fine! But I'm not sure that this is the best way to get the default pdf-program.

I'm afraid that this will only work if the default program to open pdf-files is Acrobat (because AcroExch.Document makes me a little bit suspicious).

Does anyone knows how to use the users default program to open a pdf-file and use that command (not hardcoded) to open another file-type that has another default program.

NB: at the moment everything works fine but I wonder what will happen if the user has another default for opening pdf-files


Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Test it

Have you tried changing the open command to another program and retested?
If you change the Open command, what keys remain/appear in the registry?

Test results

Hello Niek,

I've installed PDFX-viewer (portable version) and changed the default for opening PDF-files to that program.

When I look to the registry I see that my sollution will not work because it's still
HKLM\SOFTWARE\Classes\.pdf = Acroexch.Document
So my program will still open a pdf-file with Adobe, that's what I thougt it would be but not what I would like it would be

Now if I look deeper in the registry I notice that I can use the following:
HKCU\software\Microsoft\windows\currentversion\explorer\fileexts\.pdf has a new key 'Application' whith the value 'PDFXCview.exe'. That key doesn't exists if the default pdf-open program is Adobe.

So maybe what I can do is:
Look at HKCU\software\Microsoft\windows\currentversion\explorer\fileexts\.pdf\Application
If that key exists then
I have to find HKCU\Software\classes\Applications\PDFXCview.exe\shell\open\command
i have to find
HKLM\SOFTWARE\Classes\.pdf = Acroexch.Document

Do you think that this is the right way or do you know a better way to achive this

Dujardin Didier
Xpower nv

Don't know if there is

Don't know if there is better way.